Putting in case for physical sport (6)
I believe the answer is:
boxing
This clue is a double definition.
'putting in case' is the first definition.
'physical sport' is the second definition.
'for' acts as a link.
(Other definitions for boxing that I've seen before include "Packer's job" , "Ring sport" , "Fisticuffs" , "-- Day; -- glove" , "Fighting in a ring" .)