San Francisco 49ers' Colin Kaepernick might play next week

If Colin Kaepernick is plotting a come-from-behind victory in the 49ers' quarterback battle, he's surely put him in a good position.

That's because he has fallen well off the pace.

Kaepernick threw well enough on the side at practice this week that 49ers coach Chip Kelly believes the former Super Bowl starter will be able to take the field in the club's third preseason game next week against Green Bay.

But for the second week in a row, the spotlight will shine exclusively on challenger Blaine Gabbert when the 49ers, with Kaepernick watching from the sidelines, visit the Denver Broncos on Saturday night.

"He's involved in every discussion. It's not like we're telling him what to do because he's the one who ultimately knows how he feels," Kelly said about Kaepernick, who missed almost two weeks of practice and will sit out a second consecutive preseason game Saturday because of a sore right shoulder.

"It's like a lot of times when you have a muscle injury. All of a sudden, 'Hey, I feel great,' and then all of a sudden you hear the guy re-injures it because they pushed themselves a little bit too far. So, we want to err on the side of caution and make sure that he's 100-percent as we get rolling here."

Kaepernick hasn't practiced with the team since Aug. 10.

--With Kaepernick at least temporarily out of action and Thad Lewis done for the season because of a knee injury suffered in the preseason opener, the 49ers added a third healthy quarterback this week, signing veteran free agent Christian Ponder.

The 28-year-old got cups of coffee the past two seasons with the Oakland Raiders and Denver Broncos, after failing to keep his job as the starter in Minnnesota, which made him the No. 12 overall pick in the 2011 draft.

Coincidentally, Gabbert (No. 10 to Jacksonville) and Kaepernick (No. 36 to the 49ers) also were in the 2011 draft class.

Adding Ponder accomplishes several things for the 49ers even if he eventually gets cut before the start of the regular season: He gives the third unit a healthy quarterback at practice (with rookie Jeff Driskel moving up to No. 2 while Kaepernick is out); he provides insurance in case Kaepernick's injury is more serious than initially diagnosed; and he gives the team a proven option if Driskel isn't deemed NFL-ready.

Five days after signing, Ponder insisted he's ready to get thrown into the fire Saturday night.

"Yeah, I'd like to play," he said. "It won't be a full playbook. Hopefully, we come up with a plan for what I can do in the game and go out and play. It would be fun to compete and get out there."

--The 49ers had two days of joint practice sessions with the Broncos leading into Saturday's game, which gave Kelly and his coaching staff an opportunity to move some pieces around in their unsettled offensive line.

The 49ers have had first-round pick Joshua Garnett and unretired veteran Anthony Davis working out with the second team while the coaches evaluated the first unit of tackles Joe Staley and Trent Brown, guards Zane Beadles and Andrew Tiller, and center Daniel Kilgore.

Brown has been so impressive at Davis' old position of right tackle that Davis was given a look at right guard against the Broncos.

And Garnett, who initially appeared to be battling Tiller for the starting spot at right guard, was moved to the left side to compete with Beadles.

"I'm an athlete. I can play anywhere on the line," Davis said. "Right now we want the best five on the field. And Trent is not going to play guard. He's a giant man. I know I can adapt to guard, so I feel like that can help us."