PFW Ravens correspondent Jamison Hensley of the Baltimore Sun reports that Ravens C Matt Birk will be sidelined for two weeks after having arthroscopic surgery on his left knee. Hensley was told that timetable by Birk's agent, Joe Linta.
That means the six-time Pro Bowler will miss at least half of the preseason.
The team signed veteran C Casey Rabach on Tuesday to bolster the O-line depth but he can't begin practicing with the team until Thursday. In the meantime, undrafted rookie Ryan Bartholomew, out of Syracuse, has been lining up with the first-team offense.
Birk, 35, has started all 16 games each of the past five seasons. After 11 seasons with the Vikings, he has served as the Ravens' starting center the past two seasons.