ENGLEWOOD, Colo. –For the first two years of Brock Osweiler's NFL career when he lined up under center, he wasn't quite himself.

That's because Osweiler was tasked with running the scout team offense, which emulates that week's opponent so the Broncos' first-team defense can practice against what they expect to see that week.

So while Osweiler has been Andrew Luck, Chad Henne, Tony Romo, Michael Vick, Terrelle Pryor, Eli Manning and Joe Flacco this year, Wednesday was his first chance to be himself as quarterback Peyton Manning sat out the session with an ankle injury.

"To take all eight reps, especially at where we're at in the season - we're basically at the mid-point. It's nice to call your own plays (and) remember how our offense works rather than just running the scout team," Osweiler said. "I thought it was great. It was a lot of fun. We got a lot of great things accomplished today and I'm definitely better for it."

While Head Coach John Fox described Manning's injury as "nothing serious, just sore" and said that he expected the starter to return to practice on Thursday, he recognized the opportunity that was presented to Osweiler.

"That's the upside," Fox said. "We have a 'next man up,' and that includes practices. I thought that Brock conducted himself very well today. I thought it was a good experience for him."

Wednesday’s practice was the first that Manning has missed since he joined the Broncos before the 2012 season, which was also Osweiler's rookie year.

With limited practice reps to go around, Osweiler and quarterback Zac Dysert simulate theirs off to the side without the receivers or a defense.

"Obviously Peyton's taking the majority of the plays during practice so (Quarterbacks) Coach (Greg) Knapp grabs Zac and myself and we go through all the plays that we didn't get in practice so still we get to at least call out the play," Osweiler said. "We get to somewhat go through the mental rep in our head where the receivers will be and make a throw."

Osweiler said he attacks each week as if he were the starter, so the change in his practice role didn't alter his weekly preparation.

So when he found out on Tuesday that he was going lead the first-team offense for the first day of practice this week, he harkened back to his college experience at Arizona State University.

"I was the backup quarterback for two years and there were multiple times that I got called upon," Osweiler recalled. "Whether it was the first quarter the fourth quarter or to start a game – just get thrown in there. I take my experiences that I learned in college and carry them over to now. Every week I prepare like I'm the starter. When we're watching film I run through the game like I'm out there playing so if anything was to happen I can step in and hopefully the offense doesn't skip a beat."