If Realmuto can be had for Keiboom and either Fedde or Romero, as I've seen speculated, I'd have to think Rizzo does it in a heartbeat. If that happens and if Lance Lynn is signed, (2018 luxury tax be damned, I guess), as I've also seen speculated, then I'm pretty exited about this year and beyond. Lynn as the number five this year sounds nice.
Going into 2019, if Harper is re-signed then Robles or Soto are more expendable and could be made available in trade for a starter to take the role probably vacated by Gio. If Harper leaves, they have Robles and Soto to hopefully soften the blow of his departure and use the money NOT spent on Harper to replace Gio via free agency...and hopefully have enough left to extend Rendon. That's a lot to fall into place, but it's a possible path. And it's a path to NOT making December 2018 the time that the window closed on the Nats.