American Doug Barron on Monday became the first golfer to receive a ban for taking a performance-enhancing drug.
In a statement the PGA Tour said Barron, 40, had been suspended for a year for violating its anti-doping policy. It did not name the drug.
"I would like to apologise for any negative perception of the Tour or its players resulting from my suspension," Barron was quoted as saying by the Tour.
"I want my fellow Tour members and the fans to know that I did not intend to gain an unfair competitive advantage or enhance my performance while on Tour," he added.
Journeyman Barron, who turned professional in 1992, has played eight full seasons on the PGA Tour, most recently in 2006. His best finish was a tie for third at the 2005 Bryon Nelson Championship.
Since then, he has competed mainly on the satellite Nationwide Tour.
The PGA Tour launched its anti-doping programme in July last year and said, in the event of a positive doping test, it would disclose details only after the entire appeals and challenges process was completed.
The variety of sanctions could include disqualification, a one-year suspension for a first violation, up to five years for a second violation and a lifetime ban for multiple violations, plus fines up to $500,000.