The Denver Broncos have re-signed veteran center Dan Koppen, a league source told Scout.com.
The 33-year-old started 13 games for Denver last season, including their playoff loss to the Baltimore Ravens. His signing comes amid the news that fellow center J.D. Walton will have additional surgery on his left ankle that is expected to keep him out until at least October.
Koppen has started 132 of 136 career games since entering the NFL in 2003 with the New England Patriots. He joined the Broncos in September 2012 on a one-year deal.