The thing is that the Nats & Boras could agree to a deal beforehand but MLB won't allow it to be announced until the last day
Typically, teams have to have to have the rough parameters of the deal in by midnight. There is some wiggle room from what I understand provided that the initial details are entered. The thing to watch, listen for is whether or not Harper gets a physical. If that happens, a major league deal can be done.
