The lawsuit was a surprise, and so was the timing — the day before The Players Championship, the flagship event on the PGA Tour held on its home course where Singh has honed his game for the last two decades.
"I am proud of my achievement, my work ethic and the way I live my life," Singh said in a statement. "The PGA Tour not only treated me unfairly, but displayed a lack of professionalism that should concern every professional golfer and fan of the game."
Singh filed the lawsuit in New York, where he has a home and the tour has an office. He is in the field at The Players Championship.
The 50-year-old Fijian, inducted into the World Golf Hall of Fame in 2006, said in a Sports Illustrated article in January that he used deer antler spray and he was "looking forward to some change in my body." The spray was said to include an insulin-like growth factor that was on the tour's list of banned substances. The tour sent a sample from Singh to be tested, and it returned small amounts of IGF-1.
PGA Tour Commissioner Tim Finchem announced April 30 that the tour was dropping its case because of new information from the World Anti-Doping Agency, which said deer antler spray was no longer considered prohibited because it contained just minimal amounts of the growth factor.
The lawsuit claims the PGA Tour relied on WADA's list of banned substances and methods without doing any of its own research, including whether such substances even provide any performance-enhancing benefits. Singh's lawyers said the tour "rushed to judgment and accused one of the world's hardest working and most dedicated golfers of violating the rules of the game."
"We have not seen the lawsuit, just the statement," PGA Tour spokesman Ty Votaw said. "We have no comment."
Some of the details and allegations that emerged from the lawsuit:
— Finchem had proposed suspended Singh for 90 days, and his earnings from Pebble Beach and Riviera would have been redistributed.
— The tour held Singh's earnings from five tournaments — $99,980 — in escrow without authority during the investigation and appeal.
— Singh's current caddie, Tony Shepherd, recommended that he try the deer antler spray to help with his back and knee injuries.
— Scientists hired by Singh's attorneys discovered that IGF-1 is found in cow's milk. They also claim that the amount of IGF-1 in deer antler spray is so diluted that it would be comparable to pouring a shot glass of bourbon in an Olympic-size swimming pool, and then drinking a shot from the pool water.
"He's looking to reclaim his reputation and hold the tour accountable for acting irresponsible," said Jeffrey Rosenblum, one of Singh's lawyers. "He's concerned about his reputation. There should never be an asterisk next to Vijay's name."
Rosenblum also represented Doug Barron, the only player suspended under the tour's anti-doping policy. Barron sued the tour, and the case was settled. Rosenblum could not comment on the settlement, which was confidential.
The development dominated conversations at the TPC Sawgrass during the final day of practice for golf's richest tournament. Some players thought Singh surely would be suspended, and they felt he was let off the hook on a technicality. A week later, they learned he was suing the tour.
"Everybody is shaking their heads. It's unbelievable," Bob Estes said. "It seems like the tour did everything it could and everything right as the process unfolded to protect him and his reputation. Everybody is in shock that he would do that. It's not going to help his character. It's only going to hurt it. He got the favourable ruling. It's the week of The Players Championship. He lives here. He's suing his own tour."
Estes shook his head and said, "I don't think anyone saw this coming."
Masters champion Adam Scott said he could understand Singh filing a lawsuit "if he feels like that."
"I would assume Vijay thinks he's doing what's right and the tour thinks it's doing what's right," Scott said. "Overall, these situations should be managed to be avoided. We don't need this in the game of golf. Honestly, I don't believe there's a real issue with performance enhancing drugs in this game. When there's not really an issue, it's a shame that there is."
Peter Ginsberg, a sports law specialist and lead attorney in Singh's lawsuit, said the tour never bothered to analyze the trace amounts of IGF-1 in the bottle.
"What the PGA Tour accused Vijay of spraying was not a banned substance," Ginsberg said. "It was an inactive substance and could not possibly have any effect, good or bad, on Vijay. And that's something the PGA Tour easily could have determined."
Singh's reputation took a beating early in his career when he was accused of changing his scorecard in Indonesia in 1985 and banned by an Asian tour. He did not play any tour until resurfacing on the European Tour in 1989. He came to PGA Tour in 1993, and since has made more than $67 million and reached No. 1 in the world.
Singh has won the Masters and the PGA Championship among his 34 tour victories. He holds the PGA Tour record with 22 wins since turning 40. His best year was in 2004, when he won nine times. Singh has not won since the Deutsche Bank Championship in September 2008, two months after the tour's anti-doping program was launched.
The lawsuit is geared around allegations that the PGA Tour didn't do basic research the deer antler spray and should not have dragged Singh through the process.
Singh appealed the suspension, and it was scheduled for arbitration on Tuesday. Rosenblum said his group submitted its scientific findings on April 24, and that two days later the tour said it received its new information from WADA. The tour announced it was dropping the case on the day it was required to submit its briefs for arbitration.
"The PGA Tour knew or should have known all relevant facts before it wrongfully accused Singh," the lawsuit said.
Ginsberg declined to comment when asked if Singh's attorneys contacted WADA before the tour dropped its case.
"If this suit is successful, what it's going to do is make the PGA Tour more responsible in the future," he said.
Finchem appeared on Golf Channel and said he would not comment outside of what he said last week in announcing the case was dropped. Singh, meanwhile, has not spoken to reporters about any subject since releasing a statement in February confirming that he took the deer antler spray.
"If I was him, I'm not so sure I'd talk about it," Finchem said Tuesday evening in a press conference, the day before the lawsuit was filed. "I'd kind of like for it to be gone. He didn't do what he probably should have done, what we ask players to do, but it was all a function that came out as a function of his admission. I don't know what he would add to that.
"So if he wants to be quiet about it, I'm not going to argue with him about that."