LOS ANGELES – Responding to allegations that former star O.J. Mayo received improper benefits while in school, the University of Southern California basketball team will forgo any postseason play this season, including the Pacific 10 Conference tournament, and forfeit all 21 victories from its 2007-08 season.

The self-imposed sanctions, announced Sunday morning, also include a scholarship reduction and the return of money received from the NCAA tournament earned when Mayo was on the team.

“When we’ve done something wrong, we have an obligation to do something about it and that is exactly what we are doing here,” athletic director Mike Garrett said in a statement.

The Mayo scandal involves a Los Angeles events promoter named Rodney Guillory, who allegedly received more than $200,000 from a sports agent and funneled at least part of that money to Mayo in the form of cash, clothes, a high-tech television and other items.

Louis Johnson, a former Mayo confidant, made the allegations on national television in May 2008, shortly after the player had completed his only season with the team and announced that he was leaving school early for the NBA.

USC coach Kevin O’Neill learned of the sanctions in a meeting with administrators after Saturday night’s victory over Arizona State.

The coach relayed the news to a “shocked and saddened” team at a meeting Sunday morning.

“I feel terrible for our players, in particular our seniors,” O’Neill said. “They’ve been fighting through adversity.”

The university worked closely with Pac-10 and NCAA officials to investigate the matter, Garrett said. He said the school is “disappointed that rules were violated” but did not elaborate on those violations.

“While we recognize there may be additional questions about our announcement today or other alleged NCAA infractions, until the NCAA concludes its inquiries, we cannot make any further comment,” Garrett said.

Those other potential infractions involve allegations that former coach Tim Floyd delivered cash to Guillory outside a stretch of Beverly Hills cafes.

Floyd, who has denied any wrongdoing, abruptly resigned last spring. Mayo is in his second NBA season as a star guard for the Memphis Grizzlies.

The basketball program’s self-imposed punishment suggested that USC knew the NCAA was about to take action, said the director of a compliance department at a major university familiar with such investigations.

“If they’re doing all that, they know something’s coming,” said the official, who spoke on condition of anonymity.

The NCAA has a history of giving credit to schools that self-impose but nonetheless could hand down further penalties in any or all of these matters.

The postseason ban applies to this season. The reduction of one scholarship will include this academic year and the next.

USC will reduce by one the number of coaches permitted to recruit off-campus next summer and will shave 20 days off its recruiting for the next academic year.