Ricky Carioti/The Washington Post

Ross Detwiler will pitch the opening game Tuesday of the upcoming series in Philadelphia, followed by John Lannan and Gio Gonzalez. Nationals Manager Davey Johnson tweaked his rotation to have the three left-handers face a left-handed heavy Phillies lineup.

The adjustment also allows the Nationals to have right-handers Edwin Jackson and Jordan Zimmermann face the right-handed heavy St. Louis Cardinals the following series. Chien-Ming Wang, who made his first start Sunday for the Nationals in nearly three months, could also be an option to pitch against the Cardinals.

“That decision just depends on how we come out of Philadelphia, how we do in the couple games there and how I’m getting the guys ready for the postseason,” said Johnson, who is trying to also line up his rotation so Gonzalez is on track to start the first game of their opening playoff series.

Detwiler and Gonzalez will pitch on regular rest, and Lannan will get six days in between starts.