USC drew praise for agreeing to play Cal on Dec. 4 instead of trying to get the game forfeited, which was allowable under Pac-12 rules.
But a forfeit does not count as a win for bowl eligibility. So USC would have to beat UCLA and BYU if Cal forfeited per NCAA rules.
“An eligible team is defined as one that has won a number of games against Football Bowl Subdivision (FBS) opponents that is equal to or greater than the number of its overall losses (e.g., a record of 6-6, or better). Ties or forfeited games do not count in determining won-lost record.”
That explains a lot.