Obviously he wouldn't have put food out for Crusaders (7)
I believe the answer is:
saladin
'obviously he wouldn't have' is the definition.
The definition suggests a singular noun which matches the answer.
'food out for crusaders' is the wordplay.
'food' becomes 'salad' (salad is a type of food).
'out for crusaders' becomes 'in' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'salad'+'in'='SALADIN'
'put' is the link.
Can you help me to learn more?
(Other definitions for saladin that I've seen before include "Richard the Lionheart's Crusade opponent" , "Enemy of Richard I in the Crusades" , "Opponent of the crusaders" , "Richard's enemy" , "Muslim warrior" .)