Tackling forbidden in the end, a sport unfortunately isn't for defender (6,5)
I believe the answer is:
patron saint
'for defender' is the definition.
(patron saint is a kind of defender)
'tackling forbidden in the end a sport unfortunately isn't' is the wordplay.
'tackling' indicates putting letters inside (to tackle is to take possession of).
'in the end' suggests the final letters.
'unfortunately' indicates anagramming the letters (a bad or unfortunate spelling).
'isn't' becomes 'aint' (non-standard version of 'isn't').
The last letter of 'forbidden' is 'n'.
'a'+'sport'='asport'
'asport' anagrammed gives 'patros'.
'n' put inside 'patros' is 'patrons'.
'patrons'+'aint'='PATRON SAINT'
(Other definitions for patron saint that I've seen before include "Andrew for Scotland, for example" , "Virgin Mary in France possibly" , "Matthew, of tax collectors; Luke, of physicians, etc" , "Protector in heaven" , "Religious guardian" .)