Rubbish a work schedule (4)
I believe the answer is:
rota
'work schedule' is the definition.
(I've seen this before)
'rubbish a' is the wordplay.
'rubbish' becomes 'rot' (I've seen this before**).
'rot'+'a'='ROTA'
(Other definitions for rota that I've seen before include "supreme Catholic court" , "Work roster" , "Register of names for duties" , "Task list, roster" , "Working times list" .)