In order to make room for Severino, the Nationals transferred reliever David Carpenter to the 60-day disabled list.
Tanner Roark had a shortened start in the minors on Monday so that he could potentially start in Strasburg's place on Friday.
Discuss here: Joe Ross vs. Marco Gonzales.
The Nationals reliever has seen an uptick in his numbers thanks to one pitch.
Cardinals have the best ERA in baseball.
Scherzer is 0-3 with a 6.43 ERA in August
The two will also be joined by four pitchers and a catcher.
Wilson Ramos is behind the plate for Joe Ross.
His 28 RBI last month tied a Nationals record for most driven in in a single month.
At the worst time possible, the Nationals went 12-17 in August while the Mets went 20-8.
And Matt Williams's thoughts on the Nationals' potential September call-ups.
Discuss here: Gio Gonzalez vs. John Lackey.
Yunel Escobar returns to the lineup after getting hit by a pitch on the right hand on Thursday.