Search all the players before a session (4,5)
I believe the answer is:
cast about
'search' is the definition.
(I know that cast about has the is a more specific form of the action search)
'all the players before a session' is the wordplay.
'all the players' becomes 'cast' (group of actors).
'before' says to put letters next to each other.
'session' becomes 'bout'.
'cast'+'a'+'bout'='CAST ABOUT'
(Other definitions for cast about that I've seen before include "Search far and wide" , "make a search" .)