The boundaries of oarsmanship? (5)

I believe the answer is:

fours

I'm a little stuck... Click here to teach me more about this clue!

'the boundaries' is the definition.
(cricket)

'of oarsmanship?' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is found within the answer.
The remaining letters 'furs' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.