ENGLEWOOD, Colo. (CBS / AP) — A couple of fights broke out, the Broncos suffered another key injury and ongoing quarterback questions for Denver and the San Francisco 49ers marked the joint practice Wednesday ahead of the exhibition game Saturday night between the teams.

Broncos defensive end Derek Wolfe sustained a left ankle injury while pass rushing during 11-on-11 scrimmaging against the 49ers’ first-team offense. He limped off the field to the locker room, leaning on team trainers walking on either side of him.

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Coach Gary Kubiak said after practice that Wolfe rolled his ankle. There was no immediate word on the severity of the injury.

“That’s scary, especially with Vance going down,” Broncos safety T.J. Ward said. “I hope he’s all right, but, man, that was a tough one.”

On Monday, the Broncos lost starting defensive end Vance Walker to a season-ending knee injury. Walker tore his right ACL during team drills when he became entangled with a pass blocker.

The controlled scrimmaging between the teams, played out before a large crowd on hand for the last Broncos practice open to the public, included some heated moments between Denver’s offensive units and the 49ers’ defensive units. Twice, the sides got into it, fighting and shoving and grabbing each other, though a combination of players and coaches from both teams quickly got the scrums under control.

“There were a couple of situations,” Kubiak said. “It’s usually when they start talking too much. That’s what usually causes things, not so much the football.”

The fights notwithstanding, Kubiak said the joint practice was beneficial for both teams.

“That’s real football, what you saw today,” he said. “A lot of things going on, a lot of competition.”

Quarterback Christian Ponder practiced for the first time since signing Tuesday with the 49ers, whose passer corps has been depleted by injury.

Ponder was released by the Raiders in training camp last year and did not play last season but offensive coordinator Curtis Modkins expressed confidence Ponder would get a handle quickly on the 49ers’ scheme.

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“He’ll be fine,” Modkins said. “He’s smart. He’s athletic. He’ll be able to do things that we ask him to do and I expect to catch-up to speed pretty quickly.”

San Francisco lost backup quarterback Thad Lewis to a season-ending knee injury Sunday in the exhibition opener against Houston.

Colin Kaepernick, who has not been throwing any passes in practice since Thursday because of tightness in his right shoulder, was on the practice field for mental reps and took three running-play snaps, handing off every time. His competition with Blaine Gabbert for the starting job is on hold.

After practice, Kaepernick, who met with Broncos general manager John Elway and Kubiak last spring about possibly coming to Denver in a trade, stopped to sign autographs for fans and even posed with one for a selfie.

Gabbert was 4 of 7 in team drills and his last pass was intercepted by Broncos rookie safety Justin Simmons.

Broncos defenders ended up picking off passes from each of the 49ers’ succeeding quarterbacks during the 11-on-11 session. Cornerback Lorenzo Doss intercepted a deflected pass by the 49ers’ Jeff Driskel, and cornerback Kayvon Webster made a diving interception along the sideline of Ponder.

The Broncos’ quarterback competition among Mark Sanchez, Trevor Siemian and rookie Paxton Lynch remains unresolved though Kubiak has hinted a decision is coming soon. Whenever it happens, it won’t be easy.

“It’s a tough, tough decision for us,” Kubiak said. “But that’s a good thing because they’re doing their job.”

NOTES: Broncos tight end Jeff Heuerman was not able to finish practice because of tightness in his hamstrings. … Sanchez completed a deep pass to wide receiver Emmanuel Sanders for a touchdown during team drills against the 49ers defense, bringing a roar from the partisan crowd, which numbered about 5,000. … Kaepernick signed autographs and interacted with fans for about 20 minutes. … The teams get together for another joint practice on Thursday.

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