The pitching matchups will remain the same, as Jordan Zimmermann will face R.A. Dickey in the matinee, and Max Scherzer will start against Marco Estrada in the nightcap.
Per MLB rules, the Nationals get to add one player to the 25-man roster for the second game.
"We're looking at it right now," Nationals manager Matt Williams said. "There are options for us, so we haven't made a decision tonight, but we will do that tonight at some point."
Williams wouldn't confirm that the callup will be a relief pitcher, but given the amount the bullpen was used over the past week, there is a possibility that could be the decision.
Fans with tickets to Monday night's game can use their ticket and parking passes to attend Tuesday's 1:05 game. Fans unable to attend Tuesday's game can exchange them for a different game at the Nationals Park Box Office.