Jimmy Garoppolo will start against the Denver Broncos during the San Francisco 49ers' next preseason game. It will be the quarterback's first in-game action since his season-ending ACL injury last year. He's unlikely to see too much playing time as the 49ers continue their cautious approach to easing him back onto the field.

"Jimmy should be ready to go next week," head coach Kyle Shanahan told reporters on Saturday night.

C.J. Beathard will enter the game after Garoppolo, Shanahan confirmed. Nick Mullens got the start during the preseason opener against the Dallas Cowboys, and Beathard entered the game in the second half. Mullens and Beathard are competing for the backup quarterback job behind Garoppolo.

"We plan on starting C.J. next time," Shanahan said. "We had to pick (for the Cowboys game), and we went with Nick first. He was the last one to finish the season."

Mullens and Beathard have managed to not let the competition hurt their friendship.

"Me and C.J. are great friends," Mullens said after Saturday night's win. "We have a great relationship, and we both understand the business. We're just doing what we're told. Nick, it's your turn to play, C.J., it's your turn to play. That's what we do. We battle, we support each other, and it's been great so far."

Shanahan said he remains undecided on who will earn the job behind Garoppolo and Saturday night's game didn't clarify things. Neither Mullens nor Beathard separated themselves from the other, the coach said.

"I thought both of them made some good plays, but I thought both of them had definitely — each one of them had one really bad play," Shanahan explained. "I thought they threw a pick that was pretty easy to see.

"I think Nick, the backside linebacker got it in zone. I think it was C.J., a robber safety came down and got him. They both should have saw. After that, I thought they both played pretty well while under duress."

The 49ers play the Broncos at Mile High Stadium on Monday, August 19.