Sad about half the team being overfed! (5)
I believe the answer is:
sated
'overfed' is the definition.
(I've seen this in another clue)
'sad about half the team' is the wordplay.
'about' means one lot of letters goes inside another.
'half the' means to take half the letters.
'team' cut in half is 'te'.
'sad' going around 'te' is 'SATED'.
'being' acts as a link.
(Other definitions for sated that I've seen before include "Stuffed, having had a surfeit" , "given more than enough" , "Stuffed with dates" , "Stuffed, having eaten to the full" , "Fully satisfied" .)