The Pittsburgh Steelers placed center Fernando Velasco on injured reserve due to an Achilles injury suffered in a loss to the Baltimore Ravens and cut cornerback DeMarcus Van Dyke.
They signed offensive tackle Rashad Butler and center Eric Olsen.
Velasco started 11 games and played well since center Maurkice Pouncey was placed on injured reserve.
Van Dyke was signed in November.
Butler has played in 50 games with four career starts. He was released by the Cleveland Browns on Nov. 5. He spent time with the Houston Texans from 2007 to 2011. He was originally drafted by the Carolina Panthers in the third round in 2006.
Olsen has played in 17 games with four starts. He was released by the New Orleans Saints in September. Olsen originally was drafted in the sixth round in 2010.
Follow me on Twitter: @RavensInsiderAaron Wilson covers the Ravens for The Baltimore Sun.