Left league after fourth strike. Bad! (3)
I believe the answer is:
ill
'bad' is the definition.
(associated in meaning)
'left league after fourth strike' is the wordplay.
'left' becomes 'l' (common abbreviation).
'league' becomes 'l' (abbreviation).
'after' is a charade indicator (letters next to each other).
'fourth strike' becomes 'i' (4th letter of 'strike').
'l'+'l'='ll'
'll' put after 'i' is 'ILL'.
(Other definitions for ill that I've seen before include "reduced state" , "laid up?" , "Seasick" , "Out of sorts" , "Evil or sick" .)