Current teammates bigger and fitter (9)
I believe the answer is:
installer
'fitter' is the definition.
(I've seen this before)
'current teammates bigger' is the wordplay.
'current' becomes 'i' (symbol for electric current).
'teammates' becomes 'ns' ('north' and 'south' are teammates in bridge).
'bigger' becomes 'taller'.
'i'+'ns'+'taller'='INSTALLER'
'and' acts as a link.
(Other definitions for installer that I've seen before include "New software program" , "fitter" .)