Denver Broncos tight end Jake Butt grabs a water bottle during a combined NFL training camp with the San Francisco 49ers Saturday, Aug. 17, 2019, at the Broncos' headquarters in Englewood, Colo. (AP Photo/David Zalubowski)

ENGLEWOOD, Colo. (AP) — Jake Butt has had another setback in his return from a third ACL injury and might be headed back to injured reserve.

Butt played 11 snaps in Denver's preseason loss to the Los Angeles Rams last weekend in his first game action since September, leading to optimism that he could be a big boost to an offense that relies heavily on the tight end.

Butt hasn't practiced since that game, however, because of pain and swelling in his surgically repaired left knee, symptoms that also sidelined him for three weeks earlier this summer.

"His knee, when he starts to feel good and plays or practices, then it flares back up again," coach Vic Fangio said Tuesday, adding that the third-year pro from Michigan "may miss some time."

Fangio said IR is a possibility for Butt but not a certainty .

Butt, who missed the entire 2017 season after tearing his other ACL in his final game at Michigan, caught a pair of passes for 17 yards against the Rams on Saturday night, something he called, "a step in the right direction."

"I've played so little in my time here," Butt said after the game. "It's been a grind. I've been tested quite a bit. I just want people to look at this story and find hope, find faith. ... I've been tested more than most, and I've been able to overcome a lot."

His teammates were excited for him. Offensive lineman Elijah Wilkinson said, "One of our brothers is back. He works as hard as I've ever seen anybody work, and it's great to see him back."

That excitement dissipated Monday when Butt had to sit out practice, an ominous sign that he was headed for another stint on the sideline.

Injuries to Butt and four other offensive players are complicating the Broncos' 53-man roster decisions. Also injured are QB Drew Lock (thumb), right guard Ronald Leary (knee), receiving back Theo Riddick (shoulder), and fullback Andy Janovich (chest).

Also, leading tackler Todd Davis has been out with a torn calf since the first day of training camp in mid-July and Fangio indicated the veteran inside linebacker might land on IR to start the season because of his slower-than-expected recovery. Originally, Davis was expected to miss three to four weeks.

Fangio said plenty of roster spots remain available heading into the Broncos' fifth and final preseason game Thursday night against Arizona.

"I think there's still a good bit," he said, "definitely in the double digits for sure."

Fangio said quarterbacks Kevin Hogan and Brett Rypien will again split snaps with Lock sidelined and starter Joe Flacco done for the preseason after taking just 30 snaps and playing four series.

The Broncos originally planned to use the game against the Rams as their dress rehearsal for their opener at Oakland on Sept. 8, but Fangio decided to hold out all of his starters instead.

On the pregame show, Fangio said he regretted not getting his QB more work as Flacco prepares for his first regular season game since a hip injury sidelined him Nov. 4 and eventually led to his trade from Baltimore to Denver over the winter.

When asked about it Tuesday, Fangio said he wasn't going to second-guess himself.

"He did have an opportunity for a few more (snaps), but it was our decision led by me that we pulled him out of those games when we did," Fangio said. "You can't look back. If we wanted him to get more, it was there for him to get. But I feel good where he's at. He's had, I don't know the exact number, you guys probably know, I'm going to say close to 40 (snaps)."

The actual number was 30: 11 against the Seahawks and 19 against the 49ers, which followed two days of joint practices.

"There are some quarterbacks in this league that haven't had any and won't have any," Fangio said. "I think 40 is a good number for him. Maybe if we had pushed it, could've gotten him into the 50s, but I think with the extra week of practice we had and where he's at in his career I think he's in good shape."

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