That is the question. I really do not know the answer to that. Yet, when I saw him play in person in the Orange Bowl against the Sooners, his arm was plenty strong enough in a big time game.
To follow up on your other post, Brady is not known for having the strongest arm, but he does well there, Buffalo, and pretty much everywhere else.
To me, another consideration would be whether the Bills think that he would want to play in Buffalo or whether he has his heart set on playing in a "Big Market."