Broncos’ starting lineman Kuper breaks arm, out 6 weeks

Chris Kuper is helped off the field after injuring his leg against Kansas City in the 2011 regular season finale.

ENGLEWOOD, Colo. — In an offseason that has brought almost nothing but good news, the Denver Broncos got a taste of the bad Tuesday morning when one of the starting offensive linemen charged with protecting Peyton Manning, the team’s biggest offseason investment, broke his arm.

Chris Kuper spent this past offseason recovering from a dislocated ankle and fractures to his lower left fibula — injuries he suffered in the 2011 regular season finale. He suffered a broken ulna in his left forearm at Tuesday morning’s training camp session.

The latest injury is expected to sideline the Broncos’ starting right guard for six weeks.

The silver lining may be that Kuper suffered the injury so early on in training camp. With that projected recovery time, Kuper would be expected to return in Week 4 of the regular season.

The problem? Denver’s first three opponents in 2012 – the Pittsburgh Steelers, Atlanta Falcons and Houston Texas — were all playoff teams a year ago.

Kuper, a seventh-year veteran, is the most-experienced member of the Broncos offensive line. Manny Ramirez, a sixth-year player (but never a starter) replaced  Kuper in the team’s 31-3 preseason win over Chicago last week and will be the likely suitor for the vacant spot at right guard.

There is also some speculation that Orlando Franklin, who started at right tackle as a rookie last season, could move to right guard. That would open the door for either Ryan Harris, a former Broncos’ starter, or Chris Clark to slide into Franklin’s spot at right tackle.