Since leaving Detroit, Porcello won the 2016 American League Cy Young Award and Scherzer is making a strong case for his third straight National League Cy Young. Both have been aware this matchup was coming.
"Looking forward to it. We've been texting back and forth," Porcello told the Boston Globe. "We've had a good time with it and I'm sure we'll both get a kick about going against each other once the game starts."
Scherzer is looking for his first win since June 5, though he's pitched well enough to win each of his past four starts, allowing two earned runs or less in each outing. The Nationals are 1-3 in those starts and were shut out in each loss.
"I think everybody's been punched in the face before of not having success," Scherzer told The Washington Post after his last start, a 1-0 loss to the Marlins. "This is the big leagues; they are going to keep coming down your throat and keep attacking you."
Scherzer, Washington's only dependable starter of late, is 4-4 with a 6.05 ERA in 10 starts versus Boston.
Porcello allowed four runs on eight hits in 5 2/3 innings last time out in a no-decision against the Angels.
He's 1-0 with a 3.38 ERA in his lone start against Washington, an eight-inning effort in April of 2015.
The Nationals (42-40) squandered an early 3-0 lead in Philadelphia on Sunday and fell 4-3 in 13 innings on Andrew Knapp's pinch-hit walk-off home run as Washington dropped a second straight weekend series to their division rivals.
Washington managed only four hits in eight innings against the Philadelphia bullpen in the finale.
"Offensively, we've got to do more," Nationals outfielder Adam Eaton told The Post. "That's plain and simple. We score early and then we can't coast. We can't take our foot off the accelerator. We got to keep going."
The Nationals are now 6-15 in their past 21 games and fell six games behind Atlanta in the NL East.
In each of their last nine losses, they've scored three or fewer runs.
"We've got to start striking out less," Nationals manager Dave Martinez told MASN. "Putting the balls in play, driving in runs when we have the ability to drive in runs."
Boston (56-29) finished a three-game series against the Yankees on a forgettable note Sunday night, getting routed 11-1 behind starter David Price as New York blasted six home runs, including three by Aaron Hicks.
Price allowed eight runs on nine hits in 3 1/3 innings.
The Red Sox dropped two of three and traveled further away from the Yankees in the AL East race.