Instead, he's fending off rookie Tim Tebow for the backup role.
Quinn, who was acquired from the Cleveland Browns in the offseason, looked confused at times in coach Josh McDaniels' complicated system during the preseason opener Sunday night at Cincinnati.
It's just one performance, behind a makeshift offensive line and with a hodgepodge of receivers he's still getting to know.
But the rushed throws, misreads and interception returned for a 24-yard touchdown weren't exactly the kind of early impressions he wanted to make.
Watching the replay in the film room certainly wasn't any better.
"Obviously, I could've done some things better here and there," Quinn said Tuesday. "But that's why we come out here to practice, that's why we're working on it. ... Things are never always as bad as they look and never as good as they look on film."
While Quinn struggled, Orton looked cool and confident in the pocket, leading the Broncos on two long scoring drives that ended with TD passes.
Hardly a surprise there.
Orton has looked that solid, that comfortable all training camp, firmly placing his stamp on the starting spot.
His mastery of the offense is unmatched by a wide margin. Then again, being in Year 2 of the system, that should be the case.
"Feeling great with it right now," Orton said.
That was hardly the case last summer, when Orton struggled with picking up the nuances of the system. There are no Cliffs Notes available for this offense, only intense cramming.
Precisely what Quinn is undergoing now.
"It's a tough offense to learn, no question about it," Orton said. "The more you're into it, the better it gets. He's just at a starting point right now."
Even Tebow looked to have a better grasp of the system, although it was largely against third-stringers. The University of Florida star completed 8-of-13 passes for 105 yards, numbers that could've been even more impressive had Matthew Willis hauled in a long pass down the sideline that bounced off his facemask.
Or, they could've been worse, had Tebow's fourth-quarter fumble -- returned for a Cincy TD -- not been reversed by replay.
Tebow's night was punctuated by a run up the middle on the final play, a bruising 7-yard TD rumble that was reminiscent of so many in his career with the Gators.
"It was a great play," said Quinn, a former first-round pick of the Browns after a standout career at Notre Dame. "He did a great job running it in."
After the game, Tebow was besieged by autograph seekers -- in his own locker room, no less. Two media members asked him to sign some items before being booted by the Broncos' public relations staff.
Tebow simply shrugged off the episode.
Quinn's trying to do the same with his lackluster performance. He completed 6-of-16 passes for 68 yards against the Bengals.
He insisted he wasn't pressing or thinking too much on the field. And he's definitely not reading anything into the performances of Orton and Tebow.
"I think the biggest thing is you have to kind of control the things that you do out there," Quinn said. "We're all working toward the same goal."
Although Tebow is making a hard charge to become the backup, Quinn isn't taking an adversarial stance. He's there to support Tebow, offering any advice the first-round pick may need.
After all, they're in the same predicament, both brushing up on quite a foreign system.
"The terminology I'm somewhat familiar with," Quinn said. "It's something that, here and there, having a little experience in the NFL, I can kind of give him some advice."
After practice Tuesday, Quinn slipped off his shoulder pads and sauntered over to the far sideline to sign autographs.
Usually, it's Tebow among the fans, penning his name on as many of his top-selling jerseys as he can.
Quinn, though, has become just as accessible and almost as big of a crowd favorite.
He's still trailing Tebow in popularity -- like everyone else -- and the gap for the backup role may be closing as well. Quinn very well could be designated the third QB on game days, especially if the Broncos incorporate specialty packages for Tebow.
To boost his stock, Quinn realizes he needs to keep absorbing that intricate offense.
"You've got to try to move on and try to get better each day," Quinn said.