Bats set out on shelf (7)
I believe the answer is:
rackets
'bats' is the definition.
(I know this)
'set out on shelf' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'on' means one lot of letters goes inside another (as in clothing 'on' a person).
'shelf' becomes 'rack' (I can't justify this - if you can you should give a lot more credence to this answer).
'set' is an anagram of 'ets'.
'ets' placed around 'rack' is 'RACKETS'.
Can you help me to learn more?
(Other definitions for rackets that I've seen before include "rows" , "illegal activities" , "Court game" , "Organised crime" , "Walled-court ball game" .)