Jittery head of athletics with intelligence about team (7)
I believe the answer is:
anxious
'jittery' is the definition.
(I've seen this before)
'head of athletics with intelligence about team' is the wordplay.
'head of' indicates taking the first letters.
'with' is a charade indicator (letters next to each other).
'intelligence' becomes 'nous' (I've seen this before**).
'about' is an insertion indicator.
'team' becomes 'xi' (eleven, a football team).
The initial letter of 'athletics' is 'a'.
'nous' enclosing 'xi' is 'nxious'.
'a'+'nxious'='ANXIOUS'
(Other definitions for anxious that I've seen before include "Uneasy, worried" , "Worried, nervous" , "Nervy" , "Restless" , "Jittery" .)