Struggling English master played like Bradman, bagging 50 (9)
I believe the answer is:
embattled
'struggling' is the definition.
'english master played like bradman bagging 50' is the wordplay.
'english' becomes 'e' (abbreviation).
'master' becomes 'm'.
'played like bradman' becomes 'batted' (Don Bradman was a cricket batsman).
'bagging' is an insertion indicator (I've seen this in other clues).
'50' becomes 'l' (roman numeral).
'batted' enclosing 'l' is 'battled'.
'e'+'m'+'battled'='EMBATTLED'
(Other definitions for embattled that I've seen before include "Beleaguered" , "Involved in conflict" , "Beset by difficulties" , "under attack" , "Under pressure, in trying circumstances" .)