Bottom three devastated after end of season (6)
I believe the answer is:
nether
'bottom' is the definition.
('nether' can be similar in meaning to 'bottom')
'three devastated after end of season' is the wordplay.
'devastated' indicates anagramming the letters (devastate literally means destroy or lay waste to).
'after' means one lot of letters go next to another.
'end of' suggests the final letters.
The final letter of 'season' is 'n'.
'three' is an anagram of 'ether'.
'ether' put after 'n' is 'NETHER'.
(Other definitions for nether that I've seen before include "Lower; Dutch '-lands'" , "Lower, like regions or garments" , "Situated below" , "Subordinate" , "Underground" .)