tweener
n.— «The NFL seemingly invented the word “tweener,” describing a player whose height and weight makes him uncertain for a specific position. He could be a defensive end or a linebacker, a DE or defensive tackle, a linebacker or a safety. Perhaps a tight end or a wide receiver, or could wind up anywhere on the offensive line.» —“More players working out at NFL combine” by Barry Wilner Canoe (Can.) Mar. 4, 2005. (source: Double-Tongued Dictionary)