Indianapolis Colts' wide receiver Marvin Harrison has been told his knee pain is likely to persist through the remainder of the season and perhaps for the rest of his career, a source said Friday. Specialists who have examined Harrison do not view surgery as a viable option because there is no guarantee of success and would require six months of rehabilitation. Colts' coach Tony Dungy said Harrison has been medically cleared to play Sunday against New England. Harrison is urging the coaches to let him do just that.