Slides left out for teams (5)
I believe the answer is:
sides
'for teams' is the definition.
(eg football sides)
'slides left out' is the wordplay.
'left' becomes 'l' (common abbreviation).
'out' is a deletion indicator.
'slides' with 'l' removed is 'SIDES'.
(Other definitions for sides that I've seen before include "Outer edges, left and right" , "Opposing teams or facets" , "Flanks, or opposing teams" , "Lines" , "Sports teams" .)