Hurdler, perhaps, or chaser, unfortunately last of twelve (9)
I believe the answer is:
racehorse
'hurdler perhaps' is the definition.
(hurdler is a type of racehorse)
'or chaser unfortunately last of twelve' is the wordplay.
'unfortunately' indicates anagramming the letters.
'last of' indicates one should take the final letters.
The last letter of 'twelve' is 'e'.
'or'+'chaser'='orchaser'
'orchaser' is an anagram of 'racehors'.
'racehors'+'e'='RACEHORSE'
(Other definitions for racehorse that I've seen before include "runner" , "Arab possibly" , "Animal" , "hope for better?" , "Steeplechaser, maybe" .)