Green Bay Packers outside linebacker Clay Matthews had another surgery on his broken right thumb.
It's the second procedure Matthews has undergone this season on the thumb.
"They have not given me a timeline on Clay," Packers coach Mike McCarthy said.
Matthews hurt his thumb again Sunday on a sack of Steelers quarterback Ben Roethlisberger, suffering a similar injury.
Mike Neal and Nick Perry will fill in with Matthews out.
Palmer has been inactive the past five games.
Follow me on Twitter: @RavensInsider
Aaron Wilson covers the Ravens for The Baltimore Sun
MAR 07 Joel Corry
Front offices and agents of soon-to-be free agents can begin discussions this weekend.
MAR 04 Jerry Angelo
At some point, even the best partnerships in the NFL will begin to dissolve.
MAR 04 Jeff Fedotin
Amidst swirling rumors, Colts would serve as perfect team for embattled tackle.