Muhammad Abdulqaadir has the flu, but he refuses to skip training this rainy March afternoon. Between coughing fits, the once and (he hopes) future running back limbers up at Hammer Bodies, a new fitness center in suburban St. Louis. He’s short and stocky, yet improbably graceful and light on his feet. As he glides sideways with hips swiveling or accelerates with a sudden burst on the artificial grass, it’s easy to picture him darting past hapless linebackers as he did so often at Southern Illinois University, where as an all-American, he set a school record with 21 touchdowns in one season.

He sheds his windbreaker to reveal a tattoo of the number three on his right triceps—a tribute, he says, to the prophet Muhammad, who instructed Muslims to wash three times before prayers. Then, after former National Football League running back Jon Vaughn gives him some pointers, he begins practicing the drills required of all N.F.L. prospects. He sprints 40 yards in 4.4 seconds, crashing full-speed into the blue padding beyond the indoor track’s finish line, and broad-jumps nine-and-a-half feet from a standing start.

A running back with those results would normally expect to be picked somewhere in the middle of the N.F.L. draft. But for Abdulqaadir, the draft has come and gone, one of a series of startling rejections that turned his dream of a football career into a nightmare. After a stint at Coffeyville Community College, in Kansas, where he set many school records, Abdulqaadir says he agreed in late 2001 to play for Washington State in the Pac-10, one of college football’s major conferences. Then Washington State rescinded its offer, and he settled for lower-profile Southern Illinois. Following two impressive seasons there, he was the leading rusher in a national all-star game. Yet not one N.F.L. team even invited him to training camp. While two of his successors at running back for Southern Illinois have signed with N.F.L. teams, Abdulqaadir played a season of indoor football for $300 a week. Now, with his 27th birthday coming up shortly before N.F.L. camps open in July, he is honing his body and skills for one last chance.

Two of Abdulqaadir’s Coffeyville teammates still wonder why he hasn’t joined them in the N.F.L. In 2001, as a freshman, Brandon Jacobs backed up Abdulqaadir. Now Jacobs starts at running back for the Super Bowl champion New York Giants. Abdulqaadir is “most definitely good enough to play in the N.F.L.,” Jacobs says. “He could make you miss. He’s a good, tough runner. There was nothing he couldn’t do. People missed out on a great back.”

Ryan Lilja used to block for Abdulqaadir at Coffeyville. As a lineman for the Indianapolis Colts, he’s opened lanes for standout backs Edgerrin James and Joseph Addai. “Muhammad’s right up there talentwise with all those guys,” Lilja says. “He can be a starting running back in the N.F.L.” He adds that Abdulqaadir enjoyed the respect of coaches and teammates. “He didn’t stay in a clique. He had friends who were white guys, friends who were black guys, friends from the South, friends from the North. He was a born leader.”

At 5-foot-7 and 195 pounds, Abdulqaadir simply may not have been quite big enough for the N.F.L. But he and others suggest that Washington State and the N.F.L. rebuffed him for an unprecedented reason: the alleged terrorist activities of his father, Mujahid Abdulqaadir Menepta. “The way this country works, that probably was the reason he didn’t get his opportunity,” Jacobs says.

An African American convert to Sunni Islam and an associate of Zacarias Moussaoui—whom authorities once fingered as the so-called 20th hijacker—Menepta gained notoriety as one of the first U. S. citizens detained as a material witness after the September 11 attacks. According to his arrest warrant, he was investigated for destruction of aircraft, bombing conspiracy, and seditious conspiracy to levy war against the United States, among other charges.

A congressional report on 9/11 described Menepta as a member of the radical Muslim Brotherhood and vice president of overseas operations and recruiting for Fatah, the Palestinian political party. Menepta denies both affiliations. His name also surfaced in federal investigations into the bombing of the World Trade Center in 1993 and the Oklahoma City Federal Building in 1995. He pleaded guilty in December 2001 to a weapons violation but was never charged with terrorism and was released from prison in November 2002.

When Abdulqaadir, then a Coffeyville sophomore, visited his father in detention, Menepta warned that major colleges and the N.F.L. would blackball him. Abdulqaadir, who had lived apart from Menepta since 10th grade, was skeptical—but no longer. “I did everything I was supposed to do, and I didn’t get the proper outcome,” he says.

It’s an axiom among football agents that no player ever believes that the N.F.L. cut him because he wasn’t good enough. That’s why Boston sports agent Brad Blank reserves a special place in his heart for Gordie Lockbaum. In Blank’s 27 years of representing would-be pros, only Lockbaum—who finished third in 1987 in the voting for the Heisman Trophy, awarded to college football’s best player—admitted lacking N.F.L. ability. “There’s a lot of guys who have marginal N.F.L. talent,” Blank says. “It doesn’t always work out. I get hundreds of calls a year from kids who say, ‘I’m being discriminated against.'"

Still, Blank and other insiders have never heard a story like Muhammad Abdulqaadir’s: an N.F.L. prospect with a parent deemed a national security threat. The league’s flag-waving, patriotic public image invites the question of whether the N.F.L. or individual teams may have quietly decided that the son of an alleged terrorist would be bad for business.

After 9/11, the N.F.L. wrapped itself in resurgent nationalism. The 2002 ­Super Bowl featured N.F.L. stars reading the Declaration of Independence, Paul McCartney singing “Freedom,” and a Budweiser ad with Clydesdale horses bowing to the Statue of Liberty. Clutching the trophy, Robert Kraft, owner of the victorious New England Patriots, proclaimed, “We’re all patriots.” Military flyovers and the unfurling of enormous American flags have become pregame staples. No N.F.L. player has emulated baseball’s Carlos Delgado, who refused to stand for “God Bless America” in 2004, or basketball’s Mahmoud Abdul-Rauf, suspended in 1996 for remaining seated during the national anthem.

Because Abdulqaadir wasn’t rated as a top draft pick, his father’s notoriety “probably would have disqualified him,” says Tom Marino, a former N.F.L. scout. “A guy with a terrorist father—it would scare me. The directive could have come from the top: Don’t get involved with this guy.” The league, he adds, “is very, very image conscious.”

Although Abdulqaadir’s situation is unique, it does reflect broader tensions over the treatment of Muslims in the workplace. In the fiscal year ending September 30, 2007, 607 Muslims filed charges of religious discrimination with the Equal Employment Opportunity Commission, up from 284 in 2000.

Abdulqaadir’s younger brother, Khalid, then a University of Oklahoma freshman, says fellow students beat him up in the fall of 2001 because his father had defended Moussaoui. Khalid says the F.B.I. asked him to wear a wire and inform on other Muslims, but he refused. The F.B.I. declined to comment.

Khalid dropped out of school and enlisted in the Navy’s medical corps in 2002. Yet, he says, the Navy rejected his requests for assignment to Iraq. In 2004, Navy records show, he was given a lie-detector test. Khalid says he was asked if he was a terrorist, had funded 9/11, or had trained abroad with the aim of overthrowing the U.S.

Federal agents also scrutinized his brother. According to Rob Reeves, former running backs coach at Southern Illinois, F.B.I. agents showed up at the school’s football office in 2005 to conduct a background check on Abdulqaadir.

His aspirations may have given the bureau a way to pressure his father. Menepta says that twice, in 2001 and 2004, F.B.I. interrogators implied that his level of cooperation could influence his son’s N.F.L. chances.

The N.F.L. has long maintained a close association with the F.B.I. A former high-ranking bureau official heads the league security office, which vets potential draftees, and other former agents work on his staff. Teams conduct their own checks too, often using ex-F.B.I. personnel. Former agents say that the bureau and the N.F.L. have cooperated on Super Bowl security, antidrug efforts, and solving travel visa problems for players in the now-defunct N.F.L. Europe.

If Abdulqaadir had been a premier prospect, the alleged sins of his father likely would not have been visited upon him. N.F.L. teams want the best, even with some baggage. The Minnesota Vikings drafted wide receiver Randy Moss in the first round despite a battery conviction and a positive drug test. One general manager told an agent, “If Osama bin Laden’s son ran a 4.3 40, we’d draft him.” But teams give more leeway to stars than to the interchangeable masses. Abdulqaadir, who ran a 4.6 40 for scouts in 2004, was one of dozens of running backs vying for scarce spots. Bad publicity about his father wouldn’t have been worth the headache.

Seated on a rickety telephone table, Mujahid Menepta straightens a leg, then quickly bends it. “I gave Muhammad this move, giving the leg and taking it back,” the onetime running back at St. Louis’ Soldan High says proudly.

Understandably, Abdulqaadir’s father is more comfortable talking about football than about terrorism. Once a community activist, he’s become an outcast, shunned by non-Muslims who connect him to 9/11 as well as by Muslims who suspect he’s an F.B.I. informant. He’s no longer welcome at the mosque he founded in St. Louis.

His first-floor apartment in the city’s Central West End is a grim sight: mildewy walls, tattered carpet, rain leaking into a pan. Menepta recently moved back into this dilapidated brownstone, which has been in his family for half a century, after being fired from a barbecue restaurant. In less than a year there, he rose from cook to assistant general manager, overseeing 40 employees. Menepta, who had told the restaurant’s owners about his weapons conviction but not the terrorism allegations, says his rapid promotions undid him by prompting them to search his name online. “I’m being slandered all over the internet,” he says. His employer declines to explain why Menepta was let go but says it wasn’t terrorism-related.

Muhammad and Khalid live on the brownstone’s third floor with their pit bull, Tyson. Muhammad says the pet is “a reflection” of his own relentlessness. Khalid, who was honorably discharged from the Navy last year, attends community college on the G.I. Bill. Devoted to his brother, he massages Muhammad’s sore muscles after training sessions and posted a video of his football exploits on YouTube.

Even to his sons, whose mother died when they were young, Menepta has long been an enigma. He took pains to imbue them with survival skills and Islamic principles yet seemed indifferent to their everyday worries about grades or friends. By the time they were in high school, he went abroad for weeks at a time without explanation. His sons admired and resented him for valuing his religion over their well-being.

Nattily dressed in old photos, Menepta now wears jeans and a T-shirt that hangs loose on his skinny frame. He lost 30 pounds in prison earlier this decade, as well as most of his teeth—broken, he says, by guards after he took a swing at them for harassing a Muslim inmate. Sometimes he weeps or rages. When asked about the F.B.I., he says, “Excuse me, I’m getting riled up,” strides into the next room, and punches the wall.

“They had the audacity to call me a terrorist,” he says later. “I told them, ‘I’m the victim of your terrorism.’ ”

He remains guarded about his past. When I ask about his travels, he rattles off innocuous destinations like Holland and the Canary Islands. Africa? He says he’s never been there. The next day, flipping through a family photo album, we come upon a camel. “That’s Gus!” he exclaims, adding that the picture was taken during a visit to Senegal in 2000.

Born Melvin Lattimore in 1950 in St. Louis, he was the youngest of 12 siblings. He played football, boxed and, like thousands of other black teenagers in the turbulent 1960s, took up radical politics. He says he belonged to the Black Panther Party and was drawn to Elijah Muhammad’s Nation of Islam. After serving 13 months in Vietnam, he was convicted of aggravated robbery in Colorado in 1971 and imprisoned for three years.

Once out, he found a job as a Southwestern Bell salesman. In 1979, he married a nurse, Tina Goodman, and they settled in Wichita, Kansas. Muhammad, whose birth name was Drew-Amun, was born in 1981, and Khalid a year later.

Tina succumbed to breast cancer in 1986; her young sons helped shovel dirt into her grave. Soul-searching, her widower gravitated toward fundamentalist Islam. In 1989, he quit his telemarketing job at AT&T in Atlanta, where his former boss would describe him as “our very best supervisor out of a team of 22.” He changed his name to Mujahid (meaning “holy warrior”) Abdulqaadir Menepta, and his older son’s to Muhammad. They moved from a one-and-a-half-acre refurbished plantation to an Oklahoma City apartment near the mosque of Menepta’s spiritual mentor.

That same year, Menepta spent four months in Pakistan, then the staging ground for Muslims battling the Communist regime in Afghanistan. His sons stayed home with their stepmother, whom Menepta had married in 1987. According to a 2004 Department of Justice report, Menepta made the trip with an Islamic missionary group sometimes used as a cover to recruit terrorists. The group is not identified, but Menepta says it was the Pakistan-based Tablighi Jamaat, described by its leaders as apolitical. He returned to Pakistan for six weeks in 1990, according to F.B.I. records.

Menepta’s Pakistan trips drew authorities’ attention in 1993, after a car bomb detonated in a parking garage beneath the World Trade Center. Secret Service agents informed him that one of the terrorists had used the number of his Pakistani travel visa, presumably to flee the U.S. Menepta was never charged. He maintains that while evangelizing in Pakistan, he’d stored the visa in a mosque, where somebody could have copied it.

Chronically restless, Menepta moved his family back to St. Louis, where in 1992 he and his sons renovated an abandoned bakery in the crime-ridden Walnut Park neighborhood into a mosque. With police backing, Menepta and a handful of helpers drove drug dealers and hookers away from the surrounding streets.

The day after the Oklahoma City Federal Building was bombed in 1995, an anonymous phone call came into the F.B.I. The informant described Menepta as a “violent individual” and said worshippers at the mosque “openly discussed their hatred for the United States.” These allegations gained enough traction that in 2002, a federal grand jury investigated the mosque for terrorist connections.

They also thrust Menepta into conspiracy theories about the federal building’s destruction. In her 2004 book The Third Terrorist, former Oklahoma City TV reporter Jayna Davis contends that Timothy McVeigh and Islamic confederates plotted the bombing in a low-rent motel. Its former manager said Menepta stayed there in 1993, she writes. Larry Tongate, an F.B.I. agent who investigated the Oklahoma City bombing, calls the theories “garbage,” adding that “there were no ties to Middle Eastern terrorists,” and Menepta “had nothing to do with the bombing.”

As I chat with head football coach Farrell Shelton at Eureka High School, he motions sophomore running back Walter Williams over.

“Who’s the best running back ever at Eureka?” Shelton asks him.

“Me,” Williams replies.

“Besides you,” Shelton says, laughing.

Williams doesn’t hesitate to answer, “Muhammad.”

In 1996, wanting to keep Muhammad off the city streets, Menepta arranged for his son to play football at Eureka, 25 miles southwest of St. Louis. Muhammad—and before long, Khalid—began busing there under a school desegregation program.

Abdulqaadir accumulated 56 touchdowns and 4,501 yards at Eureka, but his impact transcended statistics. When he revisits the school, his former coaches recount his exploits: how so many fans flocked to watch him that a bond issue was passed to fund metal bleachers and a press box; how he rarely missed a play, sparkling on offense, defense, and kick returns; how, after penalties nullified two long touchdown runs, he scampered for a third. “We’ve never had a player who willed his team to win like Muhammad,” Shelton says.

Assistant coach Tom Sumner believes that N.F.L. teams backed away from Abdulqaadir because of his father: "They're thinking, "'His dad's a terrorist.'"

Sumner, who remembers Menepta as largely an absentee dad, says, “The kids told us their father was on a pilgrimage.” Menepta was divorced, and the boys were often alone. Once, after practice and the long ride home, Muhammad recalls, “Our dinner was two cans of corn”—the last provisions on the shelves.

Eventually, Muhammad moved in year-round with fullback Robert Pursifull, while Khalid stayed with another teammate’s family. “When Muhammad started staying here all the time, his dad came out to visit him and asked if I was okay with it,” recalls Pursifull’s mother, Deborah Wolfe. “I said, ‘Yes, he pulls his weight.’ ” She adds, “We didn’t really see his dad after that” except occasionally at football games.

Menepta showed up for the opening game of Abdulqaadir’s senior year, in 1998. He was wearing a “$1,000 coat and Gucci shoes,” says Pursifull’s stepfather, James Tracy Wolfe. Menepta told the Wolfes that he had recently returned from Kenya. After Menepta was detained in 2001, the Wolfes recalled that terrorists had bombed the U.S. Embassy in Kenya on August 7, 1998. Menepta tells me he’s never been to Kenya.

In 1999, Menepta joined the growing Muslim community in Norman, Oklahoma. At its mosque, he became acquainted with a flight-school student who was anything but a football fan. Although Menepta knew him as Shakeel, his real name was Zacarias Moussaoui.

Moussaoui sometimes came over to Menepta’s apartment for dinner. A former Al Qaeda trainee in Afghanistan, he rebuked Menepta for letting his sons play football, asserting that Islam forbids celebrating violence. “I was going to kick his butt,” Menepta says. “He was a total idiot.”

Both men befriended a Yemeni undergraduate at the University of Oklahoma named Hussein al-Attas. In August 2001, Attas drove Moussaoui to Minneapolis, where Moussaoui had enrolled in a Pan Am flight-simulator course. On August 15, a Pan Am manager contacted the F.B.I. about his odd behavior, including paying cash for tuition and showing interest only in how to take off and land a plane. Suspecting Moussaoui and Attas of plotting terrorism, federal agents arrested them on immigration violations.

Attas called Menepta, who flew to Minnesota and bailed him out on August 20. But Menepta’s arrival only heightened the agents’ fears. One agent, seeking permission to obtain a warrant to search Moussaoui’s laptop, emailed headquarters on August 22 that Menepta had an “extensive criminal history” and had been the subject of a terrorism investigation in New York City.

F.B.I. headquarters denied permission for the warrant, a decision reversed minutes after the planes hit the World Trade Center. Menepta was detained on October 11. That day, F.B.I. agents discovered a military-style rifle, a semi-automatic pistol, and a shotgun in his apartment. He was charged with violating a ban on convicted felons possessing firearms. Khalid, who was living with his father at the time, says they enjoy hunting and shooting as a sport.

Menepta was soon whisked to New York for questioning. As the plane flew past ground zero, he says, a federal air marshal told him, “Look at your work.” His attorney, Lawrence Gerzog, asked Michael Mukasey, then a federal judge and now U.S. attorney general, to release Menepta on bail. “I was essentially laughed at,” Gerzog says.

Moussaoui pleaded guilty to terrorism charges and was sentenced to life imprisonment. He testified in March 2006 that he’d been assigned to fly a plane into the White House but later retracted the confession. Menepta maintains that Moussaoui “was not a 20th anything.” He doubts Muslim ­terrorists were responsible for 9/11: “It is not ­Islamic to harm innocent people.”

On October 13, 2001, two days after his father’s arrest, Abdulqaadir tore a knee ligament late in the fourth quarter of an easy Coffeyville win. He had surgery and was sidelined for the rest of the season.

At the time, Abdulqaadir was 20 years old and one of the top junior-college running backs in the country. Dozens of schools with big-time football programs were recruiting him. Many of the same schools had pursued him out of Eureka, but his low grades disqualified him from playing for them as a freshman. Such restrictions didn’t apply to junior colleges like Coffeyville, which attracts so many premier football prospects that about a dozen of its former players, including Jacobs and Lilja, are now active in the N.F.L. At Coffeyville, Abdulqaadir gained 381 yards in one game, breaking the school record held by former Dallas Cowboy Ron Springs, and he met the academic requirements for transfer to major-college teams.

Amid the largely Christian atmosphere of the Coffeyville locker room, Abdulqaadir made no secret of being a steadfast Muslim. “He was adamant about a lot of stuff, like Muslims don’t eat pork,” Jacobs says. Yet for Abdulqaadir, football always took precedence. Rather than disrupt team unity, he participated in pregame prayers, simply omitting Jesus’ name. Football season overlaps with Ramadan, the holy month when Muslims fast from dawn to sundown, so Abdulqaadir would eat enough to maintain his strength.

After his knee injury, only a few Division One colleges were still courting him, among them Washington State. In December 2001, his recovery on course, Abdulqaadir traveled on crutches to Pullman, Washington, on a recruiting visit. There, Abdulqaadir says he signed a letter of intent to play for Washington State in return for a football scholarship.

On December 19, Menepta pleaded guilty to the weapons violation. A front-page article in the St. Louis Post-Dispatch recounted his friendship with Moussaoui and speculated that Abdulqaadir’s football career would “face a penalty.”

Within weeks, according to members of Coffeyville’s athletic staff, Washington State retracted its offer. The university contended that the surgeon who repaired Abdulqaadir’s knee had botched the procedure. “Bullshit,” Coffeyville running backs coach Dickie Rolls says. “He rehabbed perfect. He didn’t lose a step. Washington State needed a reason to step back.” Chris Ball, an assistant coach at Washington State, denies there was ever a formal offer. The school subsequently signed another sore-legged junior-college running back.

Abdulqaadir surrendered his Rose Bowl dreams and opted for a second-tier program close to home. Southern Illinois, which had won only one game and lost 10 in 2001, wasn’t worried about his father. Coach Jerry Kill needed a running back, Rolls says. “I told him this was one of the best ones I’d ever had.” Abdulqaadir gained 1,331 yards as a junior, despite starting only six games, and was named conference player of the week four weeks in a row. In his senior year, Southern Illinois won 10 games and lost two. Kill says Abdulqaadir belongs in the N.F.L. as a third-down back—a role for small, elusive players.

N.F.L. teams drafted or signed as free agents nearly half of the 110 players in the 2004 Las Vegas All-American Classic, but not the runner who led the all-star game with 52 yards on nine carries: Abdulqaadir. Most evaluators considered him a long shot to be drafted in April 2004 because of his small stature. But after the seven-round draft, teams flesh out their training-camp rosters by signing lesser prospects as free agents. “Smart and explosive, he is an instinctive football player who works hard,” Sports Illustrated’s website said in its draft preview. He “could find a spot at the next level, should he catch the ball well in a camp next summer.” Abdulqaadir was rated above Bruce Perry, a running back whom the Philadelphia Eagles drafted in the seventh round.

One N.F.L. team’s scouting report expressed concern that Abdulqaadir would have trouble escaping fast N.F.L. linebackers. But it also praised his toughness and productivity and predicted that a team would give him a chance. The New York Giants showed the most interest. After the draft, they flew Abdulqaadir to the Meadowlands for a tryout.

When his agent at the time, Thayer Lance Weaver, followed up, the Giants told him that they were disappointed in Abdulqaadir’s performance and had opted for another player. “Of all the running backs I have represented, Muhammad is probably the biggest surprise that he didn’t get picked up,” Weaver says. “I was sure he was at least going to be invited to someone’s camp.”

Asked why Abdulqaadir wasn’t signed, Giants spokesman Pat Hanlon says, “Nobody can remember the specifics.”

The abrupt end to his N.F.L. aspirations stunned Abdulqaadir. “I was loved, and then the carpet was yanked out from under me,” he says. “I got the feeling people were afraid of me.”

Or perhaps of his father. Far more than in other major sports, former F.B.I. agents handle background checks of potential pro-football draftees. Teams submit extensive lists of players to the N.F.L. security office, headed by Milt Ahlerich, former assistant director of the F.B.I. laboratory. His staff includes former agents knowledgeable about 9/11 and the subsequent investigation, says an F.B.I. alum. An executive for a sports-security firm adds that “every city has a designated ex-F.B.I. guy” for vetting draft prospects. “The F.B.I. agents do a very thorough search,” says Tom Marino, the former N.F.L. scout. “Then they will speak to you over the phone. They do not do it in writing.” The N.F.L. says it has no file on Abdulqaadir.

It’s possible that the same single-minded determination that drove Abdulqaadir to score one touchdown after another in the midst of his father’s public disgrace may have blinded him to the odds against making the N.F.L. Former Cleveland Browns scout Russ Lande, who is familiar with two N.F.L. teams’ reports on him, says Abdulqaadir was “considered a legitimate guy that could be a star” in the Canadian Football League but “was probably going to have a tough time in the N.F.L.”

Three months after the draft, the F.B.I. was still keeping tabs on Abdulqaadir’s family. Muhammad was driving Menepta’s 1988 Volvo when a woman pulled up beside him at a traffic light to tell him that wires were dangling from the bottom of his car. He was startled to find two cylinder-shaped canisters connected by a wire. He removed them and alerted Khalid, then stationed at a Navy base in California. Khalid discovered a similar apparatus attached to his car.

That same night, F.B.I. agents entered the family brownstone—looking, according to their search warrant, for “an F.B.I. electronic-tracking device”—and retrieved the canisters. A few hours later, Khalid says, federal investigators reclaimed the second device.

Abdulqaadir was working as a loan officer for a subprime-mortgage outfit in 2006 when a business contact introduced him to Jon and Britt Vaughn. Jon had played for three N.F.L. teams from 1991 to 1994, returning four kickoffs for touchdowns. His brother Britt earned degrees at two elite business schools—Wharton and Kellogg—before going to work on Wall Street. The St. Louis natives now run Infinity & Beyond Media Ventures, a branding consultancy. In 2007, the Vaughn brothers watched Abdulqaadir play for River City Rage of the United Football League, where he was named rookie of the year. They were impressed by his ability—and his saga. “I don’t understand how Muhammad was able to block out all of this and excel,” Jon tells me at Hammer Bodies. He calls Abdulqaadir a “Barry Sanders-type back,” referring to the Detroit Lions Hall of Famer. “Short, powerful, unbelievable balance.”

The Vaughns envision ­Abdulqaadir as a marketing godsend for the N.F.L., which has begun scheduling regular-season games abroad. League commissioner Roger Goodell has expressed his desire to establish franchises and hold Super Bowls overseas. The Vaughns say Abdulqaadir could recast the N.F.L. favorably in countries where the U.S. is having image problems.

The brothers now manage Abdulqaadir and pay for his sessions at Hammer Bodies. The gym’s founder—a short, sprightly former collegiate wide receiver universally known as Coach Hammer—trained Jon for the N.F.L. draft. Hammer’s other clients have included college basketball’s player of the year Tyler Hansbrough and N.F.L. cornerbacks Aeneas Williams and Dre Bly.

At his first workout in January, Abdul­qaadir gasped and sweated. By late March, he’d halved his body-fat percentage, added 10 pounds of muscle, and corrected a technical flaw known as skating: running with the knees low. Pumping the knees makes “the difference between a 4.5 and a 4.3,” Hammer says—referring to the 40-yard dash—as he exhorts Abdulqaadir, “Strike the ground! Strike!”

The Vaughns plan to invite pro scouts to test him in early July. With his father gone from the headlines, Abdulqaadir is determined to open the N.F.L.’s eyes. “I’m not bitter; I don’t blame anyone,” he says. “It’s the right time. Now that the dust has cleared, I’m still here. Can I have a legitimate shot now?”