Coach Mike Tomlin said Tuesday that Roberts (pectoral) will not play Sunday against the Seahawks, Dale Lolley of the Steelers' official site reports.
Roberts was injured against Cincinnati. Being ruled out this early in the week would suggest the veteran linebacker is dealing with a significant injury. The Steelers already have three linebackers on injured reserve. Mykal Walker and Myles Jack finished the Week 16 with the majority of snaps.