NFL.com's Ian Rapoport reported Wednesday that Lilja and the Broncos agreed to terms on a one-year contract, according to a source informed of the deal. The team later announced the deal, which was first reported by The Denver Post.
Lilja becomes another option at center for the Broncos, who lost Dan Koppen to a torn ACL on Sunday. J.D. Walton, the team's first choice at center, will miss extended time after a setback in his recovery from an ankle injury led to additional surgery.
The Broncos are currently down to Manny Ramirez at center. Like Lilja, Ramirez is a guard by trade. Lilja was a guard on Peyton Manning's Indianapolis Colts teams from 2004 to 2009.
Lilja spent the last three seasons with the Kansas City Chiefs, quietly announcing his retirement on Dec. 31. The Chiefs had approached him about returning for another season, though those talks slowed during Lilja's rehab process from surgeries on his toe and knee. He will be 32 in October.