http://msn.foxsports.com/nfl/story/5822250 Jones, who last season joined Walter Payton as the only Bears running backs to eclipse 1,300 yards, strained his hamstring while running during the physical Thursday morning. "It was something where I ran this morning kind of early. I may not have stretched as much as I should have been. It was something that just happened. It could happen to anybody," Jones said. Jones was put on a physically unable to perform list to start training camp and will be re-evaluated daily, the team said. He can come off the list at any time. After skipping voluntary offseason workouts with the team, Jones was demoted off the first team, and 2005 first-round draft choice Cedric Benson moved up to the No. 1 unit.