ENGLEWOOD, Colo. (AP) The Denver Broncos want to see if former No. 1 draft pick Jake Long is healthy enough to bolster their offensive line to protect 39-year-old Peyton Manning.

Long is scheduled to visit the Broncos on Thursday. He's also visited with the Giants and Falcons this week.

The first overall pick by Miami in 2008 and a four-time Pro Bowler, Long missed nine games last season in St. Louis with a second torn ACL in two years. The Rams released him this spring.

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The Broncos lost star left tackle Ryan Clady to a season-ending knee injury in May, leaving second-round draft pick Ty Sambrailo as Manning's presumed blindside protector.

Denver signed Ryan Harris after Clady's injury to provide an experienced backup, and Sambrailo stepped into the starting lineup and quickly impressed coach Gary Kubiak. Chris Clark enters camp as the starter on the right side.

The Broncos are installing a zone-blocking scheme that makes heavy use of two-tight end sets, which will give their left tackle plenty of help in keeping pass-rushers at bay.

Manning will have four new linemen this season regardless of who starts at left tackle. The only returning starter is right guard Louis Vasquez, who spent the last half of last season at right tackle. The left guard is Ben Garland, who hasn't started a game since 2008 at Air Force, when he was a defensive lineman.

Long has started all 96 games he's played in during his NFL career and was a first-team All-Pro in 2010.

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Follow AP Pro Football Writer Arnie Melendrez Stapleton on Twitter: http://twitter.com/arniestapleton