Screen on pitch helps cover (8)
I believe the answer is:
backstop
'screen on pitch' is the definition.
'backstop' can be an answer for 'screen' (thesaurus). I'm not certain of the 'on pitch' bit.
'helps cover' is the wordplay.
'helps' becomes 'backs' (back can mean to support or help).
'cover' becomes 'top' (topping is a kind of covering).
'backs'+'top'='BACKSTOP'
Can you help me to learn more?
(Other definitions for backstop that I've seen before include "baseball catcher" , "baseball player" .)