That ended Burnett's evening.
Over his last four starts, since the hernia was diagnosed, Burnett has a 0.98 ERA with 25 strikeouts and five walks in 272/3 innings.
"I think about it [the injury] because it is there," said Burnett, who is 2-1 with a 2.06 ERA this season. "The off day we had, it bugged me all day, and the next few days it was gone, so it comes and goes, and it is something I have to deal with."
On this night, the Phillies offense was able to back up Burnett.
In the first inning, following a single to Jimmy Rollins (one of his four hits) and a walk to Chase Utley, Ryan Howard belted a three-run home run to left-center field. It was the sixth home run for Howard, who jumped on a 92-m.p.h. fastball by starter Tanner Roark.
"I was able to put a good swing on it, and it was just carrying today," Howard said.
Cody Asche made it 4-0 with a solo home run in the second. Asche entered the game hitting .219, but facing the Nationals has boosted his spirit and statistics. This was his 10th career game against Washington. After going 1 for 4 with the home run, he is hitting .400 (14 for 35) with two home runs and five RBIs against the Nationals.
The Phillies added another run with consecutive doubles by Domonic Brown and Carlos Ruiz in the fourth and two more on Marlon Byrd's two-run single in the fifth.
Meanwhile, Burnett was having little trouble against the Nationals lineup, with the exception of Adam LaRoche.
The Nationals first baseman first broke up Burnett's no-hit bid with a one-out double in the fourth. LaRoche also hit a solo home run in the sixth for Washington's first run.
Still, it was another vintage performance.
"A.J. is a constant battler, and he just gets after it," manager Ryne Sandberg said.
Burnett now has 2,215 career strikeouts, and in the fourth inning he passed Jim Bunning for 52d on the all-time list.
"Wins and losses you can't control, and you can't control ERA, you have to throw one pitch in a time, but I do take pride in my strikeouts," Burnett said. "So that is pretty cool."