The former Ryder Cup Captain had been tied for the overnight lead at six under after the first round, but suffered a costly double bogey five on the penultimate hole of his second circuit of Colorado Golf Club.
But at three under par at the halfway stage former Masters champion Langer is still well in contention, just four behind leader Fred Couples.
The American gained four shots in his second round 68 to lead by one from compatriot Tom Kite, with Tom Lehmann a further shot back in third.
Langer carded two bogeys on his front nine but the reigning US Champions Tour Order of Merit winner seemed back to his best with birdies on the tenth and 16th.
But the dropped shots at the 17th proved costly and were followed by a bogey at the last, meaning the German will need to return to his first round form over the weekend if he is to break his Senior Major duck.
Zimbabwe's Nick Price is in a tie for sixth with Langer on three under, with Eduardo Romero one over par and Ireland's Des Smyth, South African Chris Williams and Thailand's Boonchu Ruangkit another shot further back.