Older batsmen needing replaced: that can be shown (12)
I believe the answer is:
demonstrable
'that can be shown' is the definition.
'older batsmen needing replaced' is the wordplay.
'needing replaced' is an anagram indicator (the letters must be placed elsewhere).
'older'+'batsmen'='olderbatsmen'
'olderbatsmen' anagrammed gives 'DEMONSTRABLE'.
(Other definitions for demonstrable that I've seen before include "Verifiable" , "clear" , "Able to be proved" .)