The most important player on the Washington Nationals is Bryce Harper.
That isn't exactly a hot take, what with the former National League MVP being their best player and all. There will nonetheless be an extra layer to Harper's importance to the Nationals in 2018. His looming free agency gives them a further incentive to capture an elusive World Series championship.
This is also an excuse to go get the most important player who should be on the Nationals: J.T. Realmuto.
Since he's not yet a household name, the basic need-to-know information about Realmuto is he's a 26-year-old catcher who's employed by the Miami Marlins.