Quarterback Trey Lance said in the immediate aftermath of his first NFL start that he thought his body held up fine after taking a beating with 16 rushing attempts.
But in the hours after the game, Lance began experiencing knee discomfort that warranted an MRI examination.
Coach Kyle Shanahan told reporters on Monday afternoon that Lance sustained a left knee sprain that makes him questionable for the 49ers’ Week 7 game against the Indianapolis Colts.
"He said he didn't remember doing it at any time, and he didn't feel it until he was in bed last night," Shanahan said.
Shanahan said Lance's condition should not keep him out of action for long -- if it keeps him out at all. The 49ers are currently on their bye week.
"He'll have to stay here during the bye week and get treatment and everything, so we should have a good idea by the end of next week whether he's got a chance for Indy or not," Shanahan said. "If he doesn't, they told me it should be a one- to two-week thing, but possibly just one."
The 49ers expect veteran quarterback Jimmy Garoppolo will be available for the Oct. 24 game against the Colts on "Sunday Night Football." Garoppolo was inactive for the 49ers’ 17-10 loss to the Arizona Cardinals on Sunday due to a right calf injury.
Shanahan suggested that Garoppolo will remain as the team's starting quarterback when he receives clearance to return to action.
The 49ers elevated Nate Sudfeld from the practice squad to serve as the backup against the Cardinals. He would remain in that role if Lance is unavailable for the team's Week 7 game.
Lance carried the ball 16 times and gained 89 yards in the 49ers' 17-10 loss to the Cardinals. He completed 15 of 29 pass attempts for 192 yards with no touchdowns and one interception.
"It doesn't change my opinion, big picture," Shanahan said. "Trey definitely has the ability to help us win games. I thought he was a big part of why we had a chance to win that game. I just wish we'd played better around him, too.
"Not that he was perfect by any means, but he gave us a very good chance to win that game. And I know he'll give us a chance to win a lot, going forward. . . In these three losses that we've had in a row, the answer, good or bad, is not just the quarterback. We got to play better all-around."