A sore hamstring kept Darren McFadden out of practice again on Thursday and is almost certain to miss Sunday's game against San Diego. Michael Bush will start in McFadden's place if he is unable to play on Sunday. The Raiders insist McFadden's injury isn't like the one that sidelined him early in training camp, but coach Tom Cable said it was "very, very doubtful" that the third-year pro would play Sunday.