The Cowboys officially placed rookie RB DeMarco Murray on injured reserve and signed veteran RB Sammy Morris on Tuesday.
Dallas also placed S Barry Church (shoulder) on I.R. and signed S Mana Silva off the Bills' practice squad.
Murray fractured his ankle in the Cowboys' loss to the Giants on Sunday night. He finished his rookie season with 897 rushing yards and a 5.5-yard rushing average.
Morris, 34, was a free agent. He had 56 rushing yards last season with the Patriots. Morris will likely be Felix Jones' backup.
Church had 20 tackles and an interception this season. He also had five special-teams tackles.