Condition backed by more senior cricketer, perhaps (7)
I believe the answer is:
fielder
'cricketer perhaps' is the definition.
(fielder is a type of cricketer)
'condition backed by more senior' is the wordplay.
'condition' becomes 'if' (I've seen this in other clues).
'backed' is a reversal indicator.
'by' means one lot of letters go next to another.
'more senior' becomes 'elder'.
'if' in reverse letter order is 'fi'.
'fi'+'elder'='FIELDER'
(Other definitions for fielder that I've seen before include "Slip or cover, maybe" , "One as cover, slip" , "one in gully, perhaps" , "Player" , "Cricketing slip, say?" .)