Coach Kyle Shanahan said Mullens will start Thursday versus the Raiders if C.J. Beathard (wrist) is unable to play, Matt Barrows of The Athletic reports.
After Beathard was listed as a non-participant on Monday's estimated injury report, he had trouble holding a football Tuesday as a result of a sore right wrist. With no practice yet this week, his status could come down to a game-time decision Thursday. In the event Beathard is inactive, Mullens and his zero NFL snaps would be given the nod over veteran third-stringer Tom Savage.