Capacity of rough partner in child’s play to get body for rugby league (10)

'capacity of rough partner in child's play' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'get body for rugby league' is the wordplay.
I cannot quite see how this works, but
'league' could be 'l' (abbreviation) and 'l' is located in the answer.
'get' could be 'be' ('get' can mean 'come to be') and 'be' is found within the remaining letters.
This may be the basis of the clue (or it may be nonsense).

'to' acts as a link.

Can you help me to learn more?