The other update is that rookie running back Elijah Mitchell, the team's leading rusher, is expected to play.
Garoppolo did not practice this week after suffering a torn ligament and chipped bone in his right thumb during the 49ers' Week 16 loss to the Tennessee Titans. Mitchell has been dealing with a knee injury and has not played since Week 13.
"[Thursday], I thought, was [Mitchell's] best day [of practice] that he's had, for a Thursday," head coach Kyle Shanahan said on Friday. "That's the only day we're going full speed, and he was able to get more reps than he has since this has happened to him. So, I think that's very encouraging, especially when he does that."
Rookie Trey Lance will start against the Texans if Garoppolo doesn't play. It will be his first start and significant playing time since Week 5.
"I think guys believe in Trey," Shanahan said. "I think guys expect him to go out there and play well. By no means, like everyone, is he going to play perfect. But I think that guys, they got to see him Arizona week, they got to see him this week, in terms of how he handles himself.
"And I think that it's even stronger this week. He knows how to handle the part. He knows how to get in the huddle. He takes command. His preparation is very impressive, and I think that gives the guys a lot of confidence in him."
Nate Sudfeld, who was activated from the practice squad this week, would serve as Lance's backup if Garoppolo doesn't play.