Not especially impressive batting statistic (7)
I believe the answer is:
average
'batting statistic' is the definition.
(I've seen this in another clue)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for average that I've seen before include "Mediocre - medium" , "Medium; normal" , "Mean - ordinary" , "par" , "Mean figure?" .)