I think that really depends on a couple of things: 1) Why is he falling? It would most LIKELY be due to a poor injury prognosis, meaning he might not be available until 2021. I mean his tape is already out there, he's not participating in any bowl games or the Combine, so what you have on him is what you have now. Could Ballard be that patient? Well, that all depends on 2) Sign a veteran FA for 2020 that Tua could learn and grow under while he is recovering, then let him take the reigns in 2021. However, if Tua's health report comes back more positive than expected and it looks like he plays in 2020, then I HIGHLY doubt he gets past Carolina, and probably goes to Miami.
But if the former plays out, would Ballard want to do that? THAT is the $200M question. But I would be OK with it.