Disputed claim initially about balls bowled in test (13)
I believe the answer is:
controversial
'disputed' is the definition.
(similar in meaning)
'claim initially about balls bowled in test' is the wordplay.
I cannot really understand how this works, but
'about' could be 'over' (I've seen this before) and 'over' is located in the answer.
This explanation may well be incorrect...
(Other definitions for controversial that I've seen before include "Arousing dispute" , "Debatable, likely to arouse dispute" , "Disputable" , "Likely to cause disagreement" , "Contentious" .)