During Saturday morning's practice, rookie Brock Osweiler was the second quarterback up during seven-on-seven and team drills behind Peyton Manning. Sunday afternoon, 2011 practice-squad member Adam Weber immediately followed Manning. Earlier in training camp, Caleb Hanie was the second quarterback up.

The Broncos don't have a second-string quarterback at this point; they have three of them.

"We've got a 1 and then we've got a 2a, b and c," Broncos coach John Fox said. "They'll sort that out."

Each brings a different attribute. Hanie is the only one of the understudy troika with starting experience and thus was considered the favorite for the No. 2 role when camp began. Weber is the only one with previous experience in the scheme, having played in it last year during practice. Osweiler is the only one to be drafted.

The Broncos have already anointed Osweiler their quarterback of the future, so it seems likely Hanie and Weber are scrambling for one spot. But if Osweiler proves to be the equal of the two more experienced quarterbacks, the Broncos might give him the No. 2 job based on his potentially massive upside.

Osweiler's arm is easily the strongest of the three backups, and he has done a good job keeping his elbow high on his release, only occasionally dropping it low and into a sidearm motion. The elbow point was an issue that Osweiler began to correct during his offseason sessions with Noel Mazzone, the UCLA offensive coordinator who held the same position at Arizona State when Osweiler played there.

The test for Osweiler comes when he deals with a pass rush. Sometimes he succeeds -- on Saturday, he did -- when he correctly read a safety blitz from his right and dumped off to the left side. At others he fails, as was the case Sunday, when defensive end Cyril Obiozor stormed into the backfield; Osweiler located tight end Virgil Green wide open but overshot him.

"I'm kind of going through the same growing pains I did at my high school and ASU," Osweiler said. "I've been in this position before. I know how you have to fight through it."

The Broncos hope Osweiler's future as a starter is in the long-term -- after Manning's retirement.

But if he adapts and learns his lessons quickly, he might be the Broncos' primary relief option sooner than expected.

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