Baltimore, MD -- (Sports Network) - Ravens safety Dawan Landry, defensive tackle Kelly Gregg and cornerback Samari Rolle are not expected to play this Sunday as Baltimore hosts the Tennessee Titans.

Landry left the club's September 21 victory over the Cleveland Browns late in the second quarter with a neck injury. He was taken to the University of Maryland Shock Trauma center for further testing, where it was revealed he suffered a spinal cord concussion. He did not play in last Monday's loss to Pittsburgh.

Gregg did not participate in practice in the last three days, nursing a knee problem.

Rolle was also missing from practice this week, dealing with a neck injury. He also did not play in Monday's loss.

In addition, cornerback Derrick Martin is doubtful with a shoulder ailment. Martin had limited participation in practice over the last three days.