A team's confidences (6)
I believe the answer is:
asides
'confidences' is the definition.
'a team's' is the wordplay.
'team's' becomes 'side's' (both can mean a sports team).
'a'+'sides'='ASIDES'
(Other definitions for asides that I've seen before include "Actors' remarks in an undertone" , "Remarks not for overhearing" , "Stage whisper" , "Words spoken through side of mouth, not for all to hear" , "Incidental remarks" .)