The spring catalog for the Brooks Brothers Country Club collection features polo shirts, chinos, golf pants—and three professional golfers. P.G.A. Tour golfers Scott Verplank and James Driscoll contemplate clubs in crisp khakis and logoed shirts. L.P.G.A. player Taylor Leon lines up a shot in pink cotton piqué and navy Bermuda shorts. When professional golfers dress for the green, the copy asserts, they appreciate the timeless appeal of Brooks Brothers.

Verplank, Driscoll, and Leon each have six-figure endorsement deals with the apparel brand. In addition to posing for the catalog, they wear logoed Brooks Brothers clothing for all professional golf appearances and serve as company spokespeople. Neither Verplank, who finished 12th on the P.G.A. Tour money list in 2007, nor Driscoll, who came in 24th on the "minor league" Nationwide Tour, is a household name. Leon is ranked only 79th on the L.P.G.A. Tour. But they're among hundreds of low-profile pros raking in high earnings by endorsing everything from clothing to banks to food. (See slide show.)

Professional golfers, independent agents who must pay their own tour fees and travel, have long relied on sponsors to defray costs. But during the past 10 years, the variety of sponsors and the amount they're willing to pay has skyrocketed, due largely to the rising visibility of the game—tournament attendance has increased nearly 30 percent in a little over a decade, to 10.6 million in 2007; while fans in 160 million homes could tune into the P.G.A. Tour in 1994, 500 million households can watch today—and the growth of sports marketing. There's also more money to be earned in winnings as a result of new deals with the networks, higher-priced ads, and increased global interest.

But sponsorship, unlike purse money, isn't performance-dependent, though many contracts provide bonuses for winning. Tiger Woods famously pulls in close to $100 million a year, with about 90 percent of that coming from endorsements. Second-ranked golfer Phil Mickelson has lucrative deals with Callaway Golf, Rolex, KPMG, Exxon Mobil, Crown Plaza Hotels and Resorts, and Barclays. But even relatively unknown, lower-ranked P.G.A. Tour players are juggling high-paying sponsorships, which could easily bring in a minimum of $225,000 a year, according to Todd Ciuba, a vice president at SFX, a sports-management company representing more than 60 golfers.

"If you're a first-year P.G.A. player and no one knows who you are, you're probably going to start in the $200,000 to $250,000 range, and that's just for the club deal," Ciuba says. A club deal—an endorsement by a golf club or a ball, shoe, or glove company—is usually the first endorsement a golfer gets when he turns pro. Once a golfer's agent negotiates nonclub deals, he potentially doubles the take overnight.