ENGLEWOOD, Colo. (AP) Peyton Manning will have four new offensive linemen working in front of him in 2015.
With Ryan Clady (knee) going on IR Friday, right guard Louis Vasquez is Denver's only starter returning to a position he played last season.
As it stands now, the anchor of this reconstructed offensive line is a man who didn't miss a snap for Baltimore in 2013 but whose snaps last year for the Ravens were limited.
After starting 16 games in `13, Gradkowski saw action in eight games last year after Baltimore obtained Jeremy Zuttah from Tampa Bay.
The experiences ''both taught me different things,'' Gradkowski said. ''I had a lot of great experience the 2013 year. Didn't miss a snap. Played over 1,100 snaps. Gained a ton of experienced. Played against great D-linemen. So, that helped me a ton.
''And then last year helped me just going through adversity, going from being a guy to being a backup and how to handle that and still keeping a positive attitude and working hard.''
Broncos coach Gary Kubiak, who was Baltimore's offensive coordinator last year, traded for Gradkowski as he began installing his zone-blocking scheme in Denver.
''I was around him. He did start 16 games a year before, so he's played in a lot of big football games,'' Kubiak said. ''I think he moves real well. I know he's very bright. He knows our system. I knew he'd come in here and be very competitive from that standpoint.
''But I also knew he'd be a great teacher for Matt (Paradis). Matt's a young player who's in a competition to be our starting center, and he's not only going to get to compete against Gino, but Gino's going to help him. That's the type of pro Gino is. I think that's real important.''
So, even if he wins the job this summer, Gradkowski could end up being a stop gap. He's due $1.574 million this season, the final year of his rookie contract.
That's looking too far ahead, however, for both the Broncos and Gradkowski, who's vying to become Manning's fifth center since he came to Colorado in 2012.
Gradkowski's lone year of NFL starting experience grew in importance this week when Clady's left knee buckled in a pass-blocking drill and an MRI revealed a torn ACL.
The other centers on the roster - Paradis, a sixth-round draft pick last year, 2015 fourth-round pick Max Garcia and undrafted Dillon Day - have yet to take a snap in an NFL game.
Gradkowski was the one snapping to Manning at the Broncos' organized team activities this week.
''I know that Peyton's command of the offense will make me a better player for sure,'' Gradkowski said. ''His knowledge of the game will also make me a better player. I love working with him.''
Manning is used to a revolving door of snappers in Denver, where his centers over three seasons have been J.D. Walton, Dan Koppen, Manny Ramirez and Will Montgomery. And Gradkowski said their chemistry is building every day.
''You kind of get used to the quarterback fairly quickly. We're snapping a lot. But I think what's more important is getting into synch with the guys next to me,'' Gradkowski said.
Vasquez gave Gradkowski a nice endorsement this week, saying, ''he's quick, he's smart and he's obviously been in the scheme. I like his style of play. So far, we've meshed well.''
The only times Manning had to make a huge adjustment with his pocket was his rookie year in Indy in 1998 and his first year in Denver in 2012. But he's never had an O-line that's this big of a question mark.
Rookie Ty Sambrailo is getting the first crack at replacing Clady. Second-year pro Michael Schofield, who didn't play any as a rookie, and veteran swing tackle Chris Clark will get some work there, too.
Ben Garland, a converted defensive tackle who hasn't started a game since 2009 when he was at Air Force, lined up at left guard this week ahead of Shelley Smith, a sixth-year journeyman with 11 career NFL starts.
With Vasquez returning to his natural position at right guard, the right tackle job is wide open for Clark, Schofield or Ryan Harris, who signed a one-year deal Friday.
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