Promote team, being one short, at breaks (7)
I believe the answer is:
elevate
'promote team' is the definition.
'elevate' can be an answer for 'promote' (synonyms). I am unsure of the 'team' bit.
'one short at breaks' is the wordplay.
'one short' becomes 'eleve' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'breaks' is an insertion indicator (inserted letters break into the word).
'eleve' enclosing 'at' is 'ELEVATE'.
'being' acts as a link.
Can you help me to learn more?
(Other definitions for elevate that I've seen before include "Raise up, hold aloft" , "'Raise, upgrade (7)'" , "Raise high or promote" , "Lift to higher place or position" , "Uplift" .)