Choose league sides in a predicament (6)
I believe the answer is:
pickle
'a predicament' is the definition.
(I've seen this in another clue)
'choose league sides' is the wordplay.
'choose' becomes 'pick' (picking is a kind of choosing).
'sides' suggests removing the centre (only the letters on the sides are used).
'league' with its centre removed is 'le'.
'pick'+'le'='PICKLE'
'in' acts as a link.
(Other definitions for pickle that I've seen before include "Preserve in brine or vinegar" , "tight spot" , "Preserved vegetable of informal plight" , "Preserve; mess" , "Relish for cheese" .)