Now Churchill Downs, which puts on the event, says that money might not have been rightfully his.
"An individual believed to be a member of Wes Welker's group on Kentucky Derby day was the beneficiary of an overpayment north of $14,000 on a wager due to a tote malfunction," Churchill Downs spokesman Darren Rogers said in a statement. "In turn, a letter has been sent to that individual in an attempt to resolve the error."
TMZ reported that Welker sent a friend to collect the winnings. That person was supposed to receive $42,295.35 but instead was given $57,193.90.
According to Kentucky administrative regulations, if there is an overpayment as a result of the calculation of a payout, the track is responsible and the patron holding the ticket does not have to refund the money. The regulations are not clear whether their overpayment is the result of an error in the operation of the tote machine.
Although Churchill Downs sent the letter to Welker's acquaintance offering ways to pay back the difference, Rogers told ESPN.com on Friday afternoon that the track does not expect to be paid back.
"It is our mistake and we are not worried about the recovery of the money," Rogers said. "We hope they come back to Churchill Downs and wager that $14,000 next year."
Rogers said the individual malfunction that led to the overpayment happens about once every three years at Churchill Downs.
Welker, who owns race horses, told "The Dan Patrick Show" on Friday that he never calculated how much he and his friends were due and that Churchill Downs could have underpaid them and they wouldn't have known.
He and his friends made the bulk of their money by boxing Commanding Curve, a 37-1 long shot that finished second in the Derby. A $2 exacta bet, for example, with winner California Chrome and Commanding Curve paid out $340 that day.
When pressed by Patrick to reveal how much he won, Welker hedged in his response.
"Enough," he said. "Enough to where my wife didn't hate me when I got home. Why do we have to go into numbers here? It was a good time."
As for all those $100 bills?
"People wanted autographs and pictures coming down, so I was like, 'Hey, wouldn't $100 be nicer?'" Welker said. "And they were like, 'Yes.' I was like, 'Perfect. So, here you go.'"
Welker's Derby Day Windfall Questioned
Darren Rovell discusses Churchill Downs' claim that a tote error resulted in Wes Welker being overpaid on a wager at its race track.