Also on the injury list was running back Matt Breida, who is expected to have a prominent role as Jerick McKinnon's backup. He had just one carry for three yards before exiting the game with a shoulder injury.
"I know it's going to be some time," head coach Kyle Shanahan said on Thursday night. "So, I don't know how long, but I have a feeling it's going to be some time."
The loss of Breida would be a significant one for the 49ers offense, but it does create a bigger opportunity for those fighting for the team's coveted third running back job. Among those players is second-year running back Joe Williams, who has impressed during training camp after spending all of his rookie season on injured reserve.
Williams, along with Raheem Mostert and Jeremy McNichols, will see increased reps in practice and the preseason if Breida cannot return soon.
"I thought they ran hard," Shanahan said of his backup running backs after the game. "I don't think we gave them a ton of space today. The times that we did have space, I thought they made some good runs. Then Jeremy (McNichols) came in and made some also. But, I did not think there was a lot of space in the game from what I saw.
"I know Raheem had that fumble, which it's tough for me to see. I couldn't tell on the replay, and I didn't see it live, so I'm not sure how that played out. But, I was happy with how hard they ran. It didn't seem like they left much out there."
Shanahan wants a chance to get a good look at all of the running backs during the preseason. The 49ers were rotating between Mostert and McNichols during much of the second half against Dallas.
"We try to balance it up throughout the whole preseason where we get a chance to see all the running backs," Shanahan said.
The 49ers will hold practices on Sunday and Monday before traveling to Houston where they will take part in two joint practices with the Texans before the teams' August 18 matchup.
More San Francisco 49ers News
-
Schefter believes 49ers open to trading Brandon Aiyuk or 'just about anybody'
The San Francisco 49ers made headlines over the weekend by agreeing to trade wide receiver Deebo Samuel to the Washington Commanders. While the move results in a significant dead cap hit, it allows the team to move on from an expensive and seemingly declining player. And the... -
TDN mock draft: 49ers add O-lineman with injury concern
Ohio State offensive tackle Josh Simmons felt an immediate connection with San Francisco 49ers general manager John Lynch when the two spoke at the NFL Scouting Combine in Indianapolis. Both hail from the San Diego area, where Lynch remains deeply rooted. "So we were chopping... -
Schefter: 49ers QB Brock Purdy's extension might not cost as much as most expect
The debate over how much the San Francisco 49ers should pay quarterback Brock Purdy is heating up this offseason. Some believe the 25-year-old will seek top-of-the-market money, while others argue he's worth significantly less. Most analysts agree that Purdy's next contract... -
Former NFL player explains how 49ers could benefit from paying Brock Purdy $54M annually
The Athletic's Dianna Russini and former NFL quarterback Chase Daniel discussed Brock Purdy on the Scoop City podcast, examining what his next contract might look like. The San Francisco 49ers are expected to extend their young quarterback, and many believe he will soon rank...