A source said the Bears' medical staff has expressed concern that defensive tackle Tommie Harris' knee injury might be more serious than the team first thought, but team officials rejected that idea Tuesday night. Harris hasn't practiced since after the third exhibition game Aug. 21, according to a team source. If Harris is limited or doesn't play against the Colts, he likely would be replaced in the lineup by a group including Anthony Adams, Dusty Dvoracek and promising rookie Marcus Harrison.