Sorry, but that is a red herring. How will you know that he can’t “master" holding??? Your “proof” will be that another player holds (which is 99.99999999% unlikely).
And if what is 99.99999999% likely to happen, that he makes the team easily and does hold, it is NOT proof that he “mastered” holding.
What will be proven is that whoever the Bills punter is come this session, he WILL be holding.