Tuesday marks a historic moment for the NBA, but not one it wants to commemorate. The league contends that for the first time in major professional U.S. sports, a referee will walk into prison a convicted felon on a gambling charge related to his employment.

It is an embarrassing day not only for Tim Donaghy, 41, who will report to a minimum-security federal camp in Pensacola, Fla., to start a 15-month sentence, but also for a league with a lucrative global footprint and a system of officiating that has taken a blow.

Donaghy pleaded guilty 13 months ago to felony charges of wire fraud and transmitting wagering tips through interstate commerce. He admitted to betting on NBA games, but neither the league nor federal investigators found evidence he wagered on games he worked. He was fined $500,000 and ordered to pay the NBA restitution costs.

Donaghy, enduring divorce proceedings and living in Florida with a friend, was sentenced in July. The former referee could be let out after 12 months.

"Needless to say, this is a difficult time. ... Tim is accepting of his situation," said his attorney, John Lauro. "He understands that he was going to be punished. But he's also looking to rebuilding his life. That's his hope."

A book might be in his future. "The (full) story has not come out yet," Lauro said. Donaghy, post-prison, also is considering counseling gambling addicts.

Meanwhile, the NBA awaits results of an investigation by Lawrence Pedowitz, hired by Commissioner David Stern, regarding its hierarchy of referees and potential gambling issues. Beyond reorganization of the officiating department this summer, further reform is possible because it was the FBI, not the NBA, that stumbled upon the corruption.

"Once you ruin the integrity of the sport, it is tough to regain it," said Hall of Fame basketball player and TNT analyst Charles Barkley, who has his own gambling issues. "The basketball family and fans need to know if there's anybody else involved."

The NBA says no. Donaghy's father, Gerry, a former college basketball referee, isn't so certain about the league's credibility. He remains "angry at the whole NBA — especially David Stern," he said in an interview with USA TODAY.

His son is "no worse than a lot of other people who should have been helped, not chastised, like the NBA did to him," Gerry Donaghy said. Stern "stood up there (at the Finals in June) and put on a show ... and called (Tim) a rogue referee, when there's at least 10 other guys floating around in that organization who are doing things just as bad."

Gerry Donaghy offered few specifics, preferring to emphasize his belief his son deserves punishment but shouldn't be singled out as the league's only villain.

"What has me (upset) is very simple," he said. His son "did a bad thing and he's going to pay the price. ... He doesn't have a nickel. He's sleeping on some guy's sofa that's good enough to loan it to him. He's going to jail for 15 months. He deserves all that for what he did. But there are other people who deserve something, too, and Stern's burying it."

Joel Litvin, NBA president of league/basketball operations, said the NBA "has no reason to want to continue (Tim's) suffering, no reason to want to cover anything up. That would be the worst thing we could do since, as they say, the cover-up is worse than the crime."

Donaghy betting scandal timeline

— June 20, 2007: The FBI contacts the NBA regarding referee Tim Donaghy as part of a probe into betting on league games.

— July 9: Donaghy resigns, ending a 13-year NBA career.

— July 24: NBA Commissioner David Stern labels Donaghy a "rogue, isolated criminal."

— Aug. 15: Donaghy, cooperating with federal prosecutors, pleads guilty to felony charges of wire fraud and transmitting wagering information through interstate commerce.

— Sept. 6: Donaghy's wife, wed to him for 12 years, files for divorce.

— July 28, 2008: An evaluation of Donaghy filed by his defense attorney reveals he is a "pathological gambler."

— July 29: Donaghy, facing up to 33 months in prison, is sentenced to 15 months. He says, "I brought shame on myself and my family." He also must pay a $500,000 fine.

— Aug. 6: The NBA Referees Association says a man identifying himself as Donaghy made phone calls to its offices and threatened bodily harm to employees because of public statements made about him. "That's very, very untrue," Donaghy tells USA TODAY.

— Tuesday: Donaghy set to go to prison.