LAKE FOREST, Ill. (AP) -- Chicago cornerback Charles Tillman is questionable for Sunday's game against the Detroit Lions because of knee and groin problems.
The two-time Pro Bowl pick was a limited participant in practice Friday after sitting out the previous two days. He missed practices last week because of the knee and left last Sunday's game at Pittsburgh after his groin tightened up.
Coach Marc Trestman says the Bears are ''reasonably optimistic'' Tillman will be ready to face Calvin Johnson and the Lions.
The Bears also placed defensive tackle Henry Melton on injured reserve because of a torn anterior cruciate ligament in his left knee, and signed defensive tackle Landon Cohen. Cohen has 32 tackles in 27 games for Detroit (2008-09), Jacksonville (2010), New England (2010-11) and Dallas (2013).
AP NFL website: www.pro32.ap.org