Chesspiece that is needed for new recruit (6)
I believe the answer is:
rookie
'new recruit' is the definition.
(a rookie is a new recruit or trainee)
'chesspiece that is needed' is the wordplay.
'chesspiece' becomes 'rook' (I've seen this before).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'needed' is a charade indicator (letters next to each other).
'rook'+'ie'='ROOKIE'
'for' acts as a link.
(Other definitions for rookie that I've seen before include "Raw recruit" , "New recruit as to army" , "Novice" , "Callow recruit" , "untested type" .)