Outsiders in race sure to come back (7)
I believe the answer is:
rebound
'come back' is the definition.
(I've seen this in another clue)
'outsiders in race sure' is the wordplay.
'outsiders in' suggests removing the centre.
'sure' becomes 'bound' (synonyms).
'race' with its middle taken out is 're'.
're'+'bound'='REBOUND'
'to' is the link.
(Other definitions for rebound that I've seen before include "be resilient" , "Echo back" , "Spring back on impact" , "tied again?" , "Deflection" .)