He goes in, but is often "on strike" (7)
I believe the answer is:
batsman
'he goes in but is often on strike' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he goes in but is often on' is the wordplay.
I cannot quite see how this works, but
'he' could be 'man' (I've seen this in another clue) and 'man' is found within the answer.
'on' could be 'at' (I've seen this in other clues) and 'at' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for batsman that I've seen before include "one of two on the field" , "He's either in or he's out!" , "Cricketer at the crease" , "Hitting ballplayer" , "Grace, for example" .)