ENGLEWOOD, Colo. (AP) Peyton Manning threw on his own for the first time in 3 1-2 weeks Wednesday, when more than a dozen Denver Broncos were either limited at practice or held out altogether.

Coach Gary Kubiak said Manning ''did about a half hour of throwing'' and some drill work inside the Pat Bowlen Fieldhouse with the strength and conditioning staff apart from the rest of the team.

The 39-year-old quarterback has been sidelined since Nov. 15 with a torn plantar fascia in his left foot, bruised ribs and a sore throwing shoulder.

Asked if he watched Manning's workout, Kubiak said: ''Yeah, I am definitely involved with them, whether it's film or personally (going) over there depending on what's going on that part of the day. We've got a good little process going on right now. We'll stick to it throughout the course of the week.''

Manning has said he has no timetable for a possible return because doctors cannot tell him when he'll be healthy again.

Brock Osweiler, 3-0 in Manning's place, makes his fourth start Sunday when the Broncos (10-2) host the Oakland Raiders (5-7).

Manning was one of eight players who missed practice Wednesday. Nine more were limited.

''I noticed that at practice,'' wide receiver Demaryius Thomas said. ''There are a lot of guys banged up. We're going to try to get as many back as we can so we can go out and try to get another win come Sunday.''

The Broncos had to release third-string quarterback Christian Ponder, whom they signed as insurance two weeks ago, because they were thin at safety. With T.J. Ward (ankle), David Bruton Jr. (knee) and Omar Bolden (hamstring) injured, they brought in fifth-year veteran Shiloh Keo on Wednesday.

''Shiloh has been in this scheme,'' Kubiak said. ''We drafted him in Houston, so he's played for us before, been a good special teams player. So, yeah we felt like if need be he could help us quickly from a standpoint of knowing what we're doing and helping ... on special teams.''

Keo tweaked Denver defensive coordinator Wade Phillips last week when the Broncos re-signed safety Josh Bush, telling him on Twitter, ''didn't want to pick me up, huh?''

Phillips responded that Bush had been with the Broncos in training camp but Keo knew how much he still thought of him. Yes, Keo replied, he did. But, Keo noted that it's ''still the same system'' and asked Phillips to ''keep me in mind.''

Keo, who was in the Bengals' training camp this summer, said once December rolled around he had turned his attention toward making a comeback in 2016.

''That whole Twitter thing was just an opportunity for me to stay in contact and get my name thrown around hopefully for a futures contract,'' Keo said. ''Things happen and now I'm here.''

With Bolden ailing, Kubiak said Keo is a possibility along with Emmanuel Sanders to return kicks Sunday.

In addition to Manning and the three injured safeties, tight end Vernon Davis and linebacker Danny Trevathan were in the concussion protocol Wednesday and running backs C.J. Anderson (ankle) and Ronnie Hillman (foot) missed practice, leaving Juwan Thompson and practice squad running back Kapri Bibbs to split carries.

Kubiak's offseason plan was to bridge the big gap that existed between the starters and backups. So, he gave veterans plenty of days off and the rookies and younger players plenty of extra snaps. That decision has paid big dividends as the injuries have mounted.

''I think that we made up a lot of ground. If you look at the offensive line and some of the things going on with our team injury-wise, I think the fact that we worked everybody in OTAs and were willing to play everybody early in the season, Shaq (Barrett) playing and other guys playing, I think that it's paying off in the long haul,'' Kubiak said.

''The biggest thing that I've noticed as a coach is that I don't see panic on our team. We sat in the meeting room last week and there were a lot of familiar faces missing the night before the game, but there's no panic. It's, `Let's go play. This is what we have to do tomorrow. This is who is up.' I think we've grown from that standpoint.''


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