Insignificant actor in run β but no hit (5)
I believe the answer is:
extra
This clue might be a double definition.
'insignificant actor' is the first definition.
'extra' can be an answer for 'actor' (extra is a type of actor). I'm not certain of the 'insignificant' bit.
'run but no hit' is the second definition.
'extra' can be an answer for 'run' (cricket run). I'm not certain of the 'but no hit' bit.
'in' is the link.
Can you help me to learn more?
(Other definitions for extra that I've seen before include "outside" , "Bonus; surplus" , "Supplemental" , "spotted at rear of the platoon?" , "Minor actor in crowd scenes" .)