Worker disgruntled to be reinforced (6,2)
I believe the answer is:
beefed up
'be reinforced' is the definition.
(I've seen this before)
'worker disgruntled' is the wordplay.
'worker' becomes 'bee' (a worker bee).
'disgruntled' becomes 'fed up' (I've seen this before).
'bee'+'fedup'='BEEFED-UP'
'to' is the link.
(Other definitions for beefed up that I've seen before include "reinforced" , "added strength" , "Given more support" .)