Something supportive for a sportsman (3)

I believe the answer is:

tee

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'sportsman' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for tee that I've seen before include "Where a hole starts" , "Start of a hole in golf" , "Starting peg" , "Stand" , "Drive off it, half-tittering" .)

I've seen this clue in the Evening Standard.

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