Footballer you wouldn't want to release? (6)

I believe the answer is:

keeper

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'footballer' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see a link between them that I can't see?

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for keeper that I've seen before include "Zoo attendant" , "Animal custodian; plain ring" , "Football or cricket player" , "Holder; museum official" , "Reluctant" .)

I've seen this clue in The Times.

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