Denver Broncos right guard Chris Kuper will miss 4-to-6 weeks after breaking one of the bones in his left forearm.
Kuper suffered a left forearm fracture during Tuesday morning's practice. He is expected to be replaced by veteran Manny Ramirez.
The North Dakota product has been battling back from a nasty ankle and lower leg injury suffered in the final week of the 2011 regular season.
Kuper has played in 79 career games (73 starts) with the Broncos.