Sick of being kept in reserve? (4,2)
I believe the answer is:
laid up
'sick' is the definition.
(similar in meaning)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for laid up that I've seen before include "Stayed off-green" , "Dicky" , "bet on horse" , "in sickbed" , "Saved" .)