sentences:  Blood replacement
  
  In both rugby union and rugby league, a blood replacement (also referred to as a blood substitution or blood bin) is a special kind of substitution which can be used in the case of a player having to leave the field of play temporarily to have a wound attended to.Both rugby union and rugby league are physically demanding games, so musculoskeletal injuries are common, as well as injuries to the head and neck, and fractures.