The team won't be prepared to play without him (7)
I believe the answer is:
trainer
'the team won't be prepared to play without him' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'the team won't be prepared to play without him' is the wordplay.
I cannot really see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
'him' could be 'rainer' and 'rainer' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for trainer that I've seen before include "Casual 11 ac" , "Coach - one of a pair of shoes?" , "Coach; shoe" , "Sports footwear" , "Machine that simulates the conditions of flying a plane" .)