What batsman off the mark might say is an art form (7)
I believe the answer is:
impasto
'art form' is the definition.
(impasto is a style of painting)
I can't explain the rest of the clue.
(Other definitions for impasto that I've seen before include "Thick painting technique" , "Technique using thick paint" , "Method of painting" , "Good covering of paint" , "Thickly-applied paint" .)