Kaepernick has been battling shoulder soreness and coach Chip Kelly said he will proceed cautiously.
"We don't want to throw him back out there and then have a setback right now," Kelly said after Thursday's joint practice session with the Broncos. "So, as we said before, from what we understand it's not a long-term thing, it's about just getting him back into it."
Kaepernick threw passes on the side Thursday but hasn't thrown in team drills since Aug. 10.
Kaepernick's continued absence presents Gabbert with an opportunity to separate himself in the quarterback derby.
"We'll see how this week goes," Gabbert said after Thursday's practice. "I don't know what the playing time is going to be like. Coach (Kelly) will decide that here later this week. But, it's a game. Whenever we're out there, we're playing our tails off until he tells us to come out."
Kelly hopes Kaepernick will return for the team's third preseason tilt against the Green Bay Packers on Aug. 26.
"That's the plan, is to see if we can get him ready so that he's full-go," Kelly said.
San Francisco's backup quarterbacks on Saturday will be rookie Jeff Driskel and recently signed Christian Ponder.