September 19, 2013 4:15:54 PM PDT By Michael C. Wright LAKE FOREST, Ill. -- The Chicago Bears held out cornerback Charles Tillman on Thursday for the second-consecutive day of practice leading into Sunday’s matchup with the Pittsburgh Steelers, and the team sat down receiver Brandon Marshall towards the end of the workout after he suffered tightness in his back. “Brandon had a very good practice,” Bears coach Marc Trestman said. “Then, at about the middle to late practice (he) tightened up a little bit. Just to be cautious, we pulled him out of practice. He walked around and moved around. We’ll just be cautious and we’ll have him limited tomorrow.” Having dealt with hip issues early on stemming from his third arthroscopic knee surgery, Marshall hasn’t had any issues with his back up to this point. Marshall’s back tightness isn’t expected to affect his availability for Sunday’s matchup at Heinz Field. Tillman spent most of the workout on Thursday with the team’s athletic trainers doing conditioning work, according to Trestman, who said the cornerback took part in walk-throughs near the end of the sessions. “We worked actively with the trainers,” Trestman said. “He was limited.” In other injury news, the Bears listed tight end Martellus Bennett (shoulder) and guard Kyle Long (back) as having participated fully at practice. For the Steelers, running back Le'Veon Bell (foot), cornerback Curtis Brown (illness) and defensive end Brett Keisel (calf) participated fully, as did defensive tackle Steve McLendon (hamstring), and tight end Heath Miller (knee). Pittsburgh cornerback Cortez Allen (ankle) did not practice, and linebacker Jarvis Jones (heel) participated in a limited capacity.