Garoppolo has a high-ankle sprain and is out indefinitely, Adam Schefter of ESPN reports.
Garoppolo exited in the third quarter of this past Sunday's loss to the Seahawks and didn't return. This injury has been nagging Garoppolo since Week 2, and the team has decided to shut him down until he can fully recover. There's a good chance that he's placed on IR, which would keep him out until at least Week 12. Nick Mullens is expected to be San Francisco's starting quarterback this Thursday against the Packers, while C.J. Beathard serves as the backup.