The Broncos are placing fourth-round pick center/guard Philip Blake on IR, and promoting center C.J. Davis from the practice squad to take his place on the 53-man roster. Adam Grant, who spent the 2011 season on Denver's practice squad, will rejoin the group in place of Davis.
Blake was inactive for Denver's first two games and was listed on the team's injury report as having a "Thump" issue which limited his practice on Saturday. So, either thump injuries are a big deal, or something else has happened to Blake.
Davis made the team out of training camp but was cut loose to facilitate the addition of veteran center Dan Koppen.