Protection for a fieldsman? (5)

I believe the answer is:

cover

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'protection' is the definition.
(I know that cover is a type of protection)

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for cover that I've seen before include "Totally obscure" , "Fielder" , "Extend over (an area)" , "Lid or shelter" , "Enshroud" .)

I've seen this clue in the Evening Standard.

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