Small bar at Old Trafford's temporarily free (4)
I believe the answer is:
bail
I believe this is a double definition.
'small bar at old trafford's' is the first definition.
(part of a cricket wicket)
'temporarily free' is the second definition.
(to bail a prisoner is to free them temporarily)
(Other definitions for bail that I've seen before include "In cricket, wooden cross-piece placed on stumps" , "Horizontal piece of cricket wicket" , "Piece of cricket equipment; surety" , "Scoop water out of (a boat)" , "Piece of sporting apparatus" .)