Reserves come back to draw, making a try (7)
I believe the answer is:
attempt
'a try' is the definition.
('attempt' can be a synonym of 'try')
'reserves come back to draw' is the wordplay.
'reserves' becomes 'ta' (I've seen this in other clues).
'come back' shows that the letters should be reversed in order.
'to' says to put letters next to each other.
'draw' becomes 'tempt' (I've seen this before).
'ta' in reverse letter order is 'at'.
'at'+'tempt'='ATTEMPT'
'making' is the link.
(Other definitions for attempt that I've seen before include "bid to kill someone" , "Try, make an effort" , "Try to climb (a peak)" , "Endeavor, try" , "Shot" .)