SANTA CLARA -- The 49ers are keeping the door open for veteran quarterback Jimmy Garoppolo to play Sunday against the Houston Texans.
The team officially listed Garoppolo as doubtful for Sunday's game. Rookie quarterback Trey Lance appears likely to get his second career start this weekend.
Coach Kyle Shanahan said he is not ready to announce that Lance will definitely start against the Texans.
"He's not out, so I'm holding out hope," Shanahan said of Garoppolo.
"We were told each day that we can push it off one more, it gives him a better chance. We're trying to hold off throwing until tomorrow (Saturday), possibly Sunday."
Practice squad quarterback Nate Sudfeld was flexed up to the roster to be available for Sunday's game.
Garoppolo sustained a torn ligament in his right thumb in the 49ers' game on Dec. 23 against the Tennessee Titans. He played the second half with the injury and said he had to make adjustments to his throwing style to compensate for the injury.
Garoppolo did not practice on Wednesday or Thursday due to the injury. Offensive coordinator Mike McDaniel on Thursday suggested Garoppolo has looked good while throwing but the functionality of the thumb was difficult to predict.
"It's more about how it responds and how it feels so that you can have strength in that thumb through the course of an entire game," McDaniel said. "So it's looked great. It's more about how he responds to it and how it feels the next day. That's why it's kind of a day-by-day basis with him."
Lance, the No. 3 overall pick in the 2021 NFL Draft, has not attempted a pass since Oct. 10, when he started and played the entire way in a 17-10 loss to the Arizona Cardinals while Garoppolo was out with a calf injury.
On the season, Lance has played 116 offensive snaps. He's completed 25 of 48 (52 percent) for 354 yards with three touchdowns and one interception. He is also the team's fifth-leading rusher with 137 yards and one touchdown on 30 rushing attempts.
The 49ers (8-7) would clinch a playoff spot on Sunday if they defeat the Texans and the New Orleans Saints lose to the Carolina Panthers. The 49ers' game kicks off at 1:05 p.m. at Levi's Stadium, but the Saints-Panthers game starts 20 minutes later.
The 49ers are 7-0 in games this season in which Garoppolo has not thrown an interception. They are 1-6 in games in which Garoppolo has thrown a pick. He threw two interceptions in the 49ers' 20-17 loss to the Tennessee Titans in Week 16.