USC leading scorer Chimezie Metu received a half-game suspension and was forced to give up his role as team captain after being ejected for striking Washington State's Carter Skaggs in the groin during Sunday's 89-71 win, the Trojans announced.
Head coach Andy Enfield said Metu must also issue a written apology as part of his discipline, which was approved by the Pac-12.
Metu will sit out the first half of Thursday's game at California.
"We commend USC and its leadership for taking swift action in response to this incident," Pac-12 commissioner Larry Scott said in a prepared statement, adding that the conference would take no further action.
Metu was tossed late in the first half Sunday, when he closed out on Skaggs and struck him in the groin after Skaggs attempted a 3-pointer. Officials reviewed the play and called Metu for a flagrant foul 2 and ejected him.
Metu wrote a letter apologizing to Skaggs and Washington State, as well as to his USC teammates.
"A lack of judgment for a split second led to an action that I immediately regretted and had no business committing in the first place," Metu wrote. "I understand there is no place in the game of basketball for such an unsportsmanlike action."
Metu is averaging 17.8 points and 7.6 rebounds per game.