Disheartened Euell quits team (6)
I believe the answer is:
eleven
'team' is the definition.
(eleven is a kind of team)
'disheartened euell quits' is the wordplay.
'disheartened' says to hollow out the word (remove centre letters).
'quits' becomes 'even' (as in 'call it quits').
'euell' with its middle taken out is 'el'.
'el'+'even'='ELEVEN'
(Other definitions for eleven that I've seen before include "Number killed in the Peterloo massacre" , "Football team; number" , "Number on a soccer team" , "Number on a side (6)" , "Enough for a team" .)