OWINGS MILLS, Md. (AP) -- Baltimore Ravens center Matt Birk is planning to have arthroscopic surgery on his left knee in the next few days, according to his agent.
Birk's agent, Joe Linta, says the six-time Pro Bowl center should be able to return in a few weeks.
The Ravens signed former Washington Redskins center Casey Rabach to a two-year contract on Tuesday to back up Birk, who played in all 16 games for Baltimore last year despite having knee problems.
The 35-year-old Birk has not practiced with the team this week, but hopes to be ready for the Sept. 11 opener against Pittsburgh.