Caleb Hanie
Caleb Hanie looks poised for another shot to win the Broncos' backup QB derby. (Andrew Mason)

Peyton Manning is expected to play well into the third quarter for the Broncos against San Francisco on Sunday, but that's nothing earth shaking. This is the week when first-teamers play beyond halftime, and in 10 previous preseasons with the Broncos and Panthers, coach John Fox has shown a tendency to play the starters for at least a series in the third quarter -- and perhaps into the early moments of the fourth quarter when he hasn't seen what he'd like from them.

But who will be up next behind Manning? Caleb Hanie took the second-team repetitions in the preseason opener at Chicago, and rookie Brock Osweiler handled the same work nine days later at Seattle. Osweiler could have seized the job, but struggled in his second-team work, leading the offense to just one first down on five possessions.

That could lead the Broncos back to Hanie, the ex-Chicago understudy who was signed in March with the intention of being Manning's primary backup. With Manning playing into the second half, there will likely be time for only one of Denver's backup quarterbacks to play, and offensive coordinator Mike McCoy offered an indication that Hanie would get the call Sunday.

"I believe he will," McCoy said when asked Friday whether Hanie would play.

During Friday's practice, Hanie was the second quarterback up and saw a handful of snaps behind the first-team offensive line. This ran counter to the Broncos' tendency to rotate the second-team snaps among Hanie, Osweiler and 2011 practice-squad QB Adam Weber during training camp.

Leonhard works with second team: Safety Jim Leonhard took another step in returning to full speed following the torn patella tendon he suffered last December, working in team periods for the first time since then -- and first time as a Bronco.

Leonhard worked primarily on the second team alongside Quinton Carter. Rahim Moore and Mike Adams are currently the first-team safeties.

"I didn’t focus on him, specifically, but some of the coaches said that he fit in," said defensive coordinator Jack Del Rio. "You can tell he has great awareness and anticipation of things. We’ll continue to get him worked into it."

Added Fox: "It was his first padded practice. I thought he moved around well."

Leonhard is expected to get a look on punt returns. He joined WRs Matt Willis and Andre Caldwell and CB Syd'Quan Thompson in working with the punt-return unit during Friday's practice.

Whether Leonhard plays Sunday is up in the air, but Fox sounded a note of caution.

"We'll take it slow, obviously, just like with all our injured players," said Fox, who has been deliberate about returning players to the lineup after injuries.

Not practicing: DE Jason Hunter (torn triceps muscle), RG Chris Kuper (broken forearm) and LBs Mike Mohamed (hamstring) and Keith Brooking (hamstring) all sat out. WR Tyler Grisham was placed on the waived/injured list after being unable to overcome a knee injury that dogged him through most of training camp.

Back to work: DT Kevin Vickerson was cleared to practice after missing the last week because of a concussion; he rotated in with the first and second teams. He was also cleared to play Sunday, Fox said.

For up-to-the-minute Broncos updates, follow Andrew Mason on Twitter at @CBSSportsNFLDEN and @MaxBroncos.