LOS ANGELES — Southern California tailback Joe McKnight did not travel with the Trojans to the Bay Area for Saturday's Emerald Bowl.
"He has some paperwork he needs to do and it's best for him to stay in L.A. so he can be available to finish it," Trojans coach Pete Carroll said.
Carroll did not have a timetable for McKnight's return.
"We don't know right now how long this will take," he said.
USC has previously said it was investigating whether McKnight used an SUV registered to a Los Angeles businessman. The Trojans also declared three players academically ineligible on Monday.
Tight end Anthony McCoy and tackle Tyron Smith, both starters, and defensive end Averell Spicer, a key reserve, will not play Dec. 26 in San Francisco.
McCoy and Spicer are seniors. Smith is a sophomore.
The Trojans (8-4) are coming off their worst season since 2001. USC had won seven consecutive Pac-10 championships and played in seven consecutive BCS games before this season.