To add more depth at center, the Ravens waived backup fullback Jason McKie and signed offensive lineman Bryan Mattison from the practice squad.
The Ravens needed another center because starter Matt Birk is questionable with a knee injury. He didn't practice for two days this week before being limited Friday.
If Birk gets sidelined during the game, the Ravens had only one other center in Chris Chester (Marshal Yanda would have been another option but he starts at right tackle). That's why the Ravens decided to promote Mattison, who is the son of Ravens defensive coordinator Greg Mattison.