Muir, a sixth-year veteran, has appeared in 46 games with 26 starts during his career with the New York Jets, Indianapolis Colts and Green Bay Packers. His total numbers include 130 tackles (100 solo), 0.5 sacks and one PD.
Muir spent part of the 2012 season with the Jets, seeing action in three games and making three tackles.
The 6-foot-2, 322-pounder had his best season in 2009 with the Colts, when he appeared in all 16 games, making 10 starts, and totaling 66 tackles (54 solo) with 0.5 sacks.
The 30-year old originally signed with the Packers as an undrafted free agent in 2007 out of Kent State.
This is a curious signing for the Raiders as they were in need of making a move to sign a third string quarterback. The team now has five defensive tackles on the roster.
Oakland has also re-signed OL Jack Cornell to the practice squad. Cornell had been activated to the roster for last week's game and then waived. He cleared waivers and was re-signed.