ENGLEWOOD, Colo. -- Being Peyton Manning's backup doesn't exactly keep you on the edge of your seat every play.
Apart from the 2011 season, which he missed in its entirety due to surgery on his neck, Manning has started every game since he was drafted in 1998.
Still, knowing there is an ironman starter in front of him doesn't keep Brock Osweiler from preparing as if he'll be under center on Sundays. That occasion doesn't arrive very often, but in 2013, a few opportunities with the first team emerged late in blowout victories or in practice, when Manning occasionally took Wednesdays off.
But the preseason still offers the most in-game action for the third-year quarterback, and it's almost that time of year again. With the starters expected to go less than a full quarter Thursday night against the Seahawks, Osweiler should have around half the game to show how much he's grown since his sophomore campaign.
"From the way practices have gone from the start of training camp, and even back to OTAs, I feel like a completely different quarterback," Osweiler said after practice Tuesday. "I feel like I'm playing at a much higher level than I did last year and especially my rookie year."
"I have very high goals for myself and very high expectations and I expect to play well Thursday."
As several Broncos have alluded to, the matchup with Seattle will be a solid measuring stick to see the team's progress. Likewise, Osweiler will face a strong test and look to improve upon last year's preseason performance in Seattle, when he went 9-for-14 for 66 yards and an interception.
"There's no other team I'd rather play, first preseason game," he said. "They have a very talented defense that flies around and gets after it. So I think it'll be a great challenge for us, but I'm excited for that challenge and I think it'll be a lot of fun."
Like many quarterbacks, Osweiler has had his ups and downs in practice, but has certainly made progress. His deep ball has become lethal at times and Offensive Coordinator Adam Gase has seen improvement just since OTAs.
"He was really aggressive and probably turned the ball over a little bit too much in the spring and he knew that," Gase said during the first week of training camp. "We sat down and [Quarterbacks] Coach [Greg] Knapp did a good job of [saying], 'Hey, training camp now, we have to start playing like it's a game.'"
"He has done a good job out here so far as far as protecting the ball, not turning it over, getting through his progressions, making sure he is getting completions and moving the sticks."
How Osweiler plays when it actually is a game will go a long way toward convincing onlookers he is capable of succeeding Manning when the time comes. If all goes according to plan for Bronco fans, Osweiler won't see the field again until at least the 2015 preseason, making this preseason an important opportunity. That starts with Seattle Thursday night.
"We're just trying to get positive plays every snap and eliminate all the negative plays that we can," he said. "I think the first preseason game is all about taking what you've learned in the classroom and applying it to the field."
"It's a basic game plan, and just sticking to your rules and just getting as many completions as you can, and getting first down after first down and hopefully move the offense a lot."