Garoppolo (thumb) sat out Thursday's practice, Eric Branch of the San Francisco Chronicle reports.
According to Branch, Garoppolo was in attendance for the workout, but he wasn't in uniform and was seen speaking with a team doctor before retreating to the weight room. The consecutive absences from practice don't inspire much confidence that Garoppolo will be ready to go for Sunday's game against the Texans while he contends with what head coach Kyle Shanahan classified as a Grade 3 UCL sprain of the quarterback's right thumb. Rookie Trey Lance directed the first-team offense Wednesday and Thursday and looks to have the edge on the Week 17 starting nod, though a final decision likely won't be made until the 49ers have a chance to evaluate Garoppolo on Friday.