Rookie quarterback Trey Lance is expected to be sidelined for seven days due to a small fracture to a finger on his throwing hand, 49ers coach Kyle Shanahan said on Monday.
The setback is likely to end any speculation about the 49ers' starting quarterback to open the season. Veteran Jimmy Garoppolo appeared to be ticketed for a Week 1 start even before Lance's injury.
Lance, the No. 3 overall pick in the 2021 NFL Draft, sustained the injury when his right hand hit the helmet of a Las Vegas Raiders pass rusher during a pass attempt in the preseason finale at Levi's Stadium.
Shanahan declined to reveal which finger Lance injured. Lance appeared to be holding his right index finger or thumb after the play in question.
"It wasn't bothering him much because he thought it was jammed on that helmet," Shanahan said. "And when you get all the images on it, they showed it to me, it's a micro-chip of a bone that's off. He chipped it, which is a small-chip fracture, which is worse than a jam.
"He can't take snaps and do all that stuff right now. He just has to rest it for seven days, they say. And that should let it heal, and hopefully he'll be good next Monday when we get into practice."
The 49ers have begun preparations to face the Detroit Lions on Sept. 12 in the regular-season opener for both teams.
Lance and presumptive starter Jimmy Garoppolo rotated into the action in the 49ers' first two drives on Sunday. Garoppolo played 14 snaps, while Lance entered for 10 plays. Lance took over and played the next four possessions before third-stringer Nate Sudfeld finished the game.
In three preseason games, Lance completed 19 of 41 pass attempts (46.3 percent) for 276 yards with three touchdowns and one interception. His passer rating was 83.0. He gained 16 yards and one touchdown on seven rushing attempts.
In other injury news, offensive lineman Shon Coleman had a triceps strain and will be out "a while," Shanahan said. Receiver Travis Benjamin remains in the NFL's concussion protocol.