Mullens received the start in place of C.J. Beathard, who is nursing injuries to his right wrist and thumb.
“Yeah, definitely we’ll consider it,” Shanahan said of the possibility of making a permanent switch to Mullens. “Definitely not thinking about that right now, but our whole team played very well. Nick definitely did.”
Shanahan said he doesn't place sole blame on Beathard for the team's five consecutive losses with him as the starter. The 49ers return to action Monday Nov. 12, against the New York Giants at Levi's Stadium.
“I don’t put all those struggles on just C.J.,” Shanahan said. “I think people make a huge mistake just saying, ‘If you win, it’s the quarterback. If you lose, it’s the quarterback.’ There are 11 guys on offense. There are 53 guys on our team. I thought our team had probably our best game of the year so far. That’s nothing against C.J. I think C.J. would have played well tonight, too, if he played.”
Beathard is 102-of-169 passing (60.4 percent) for 1,252 yards and eight touchdowns with seven interceptions and a passer rating of 81.8.
On Thursday, Mullens completed 16 of 22 passes for 262 yards and three touchdowns with no interceptions. His passer rating was 151.9.