Despite taking two of the first three against Washington, Milwaukee is fighting from behind for the National League's second Wild Card berth. With 10 games remaining on the Brewers' schedule, they trail the Cardinals by 2 1/2 games.
"I think the position that we're in now, we know we have to play great baseball," Brewers manager Ron Roenicke said before Sunday's game. "That doesn't mean we have to win every single game. And I don't think that the feeling of you have to win every game is a good atmosphere to put on a team when you go out to play every day. When you've got three games to go, OK."
The Nationals are 3-3 on their seven-game homestand and lead the Braves by 4 1/2 games in the NL East. The club already has clinched a playoff spot and has a magic number of six for the division title.
Marco Estrada, who debuted in the Majors with the Nationals, will take the ball for the Brewers against Jordan Zimmermann.
Estrada (4-6, 3.56 ERA) pitched in 15 games for Washington in 2008 and 2009 and has now found success with Milwaukee. The right-hander has allowed one or no earned runs in five of his last six starts and has tossed 13 2/3 scoreless frames over his last two.
On Wednesday, Estrada said he felt "out of whack" in the bullpen beforehand, but that didn't stop him from holding the Pirates to three hits in seven innings.
"He's definitely a hard guy to square up and do any damage against," Pirates first baseman Garrett Jones said. "He's pitching his [tail] off."
Zimmermann (11-8, 2.96) has bounced back from allowing a career-worst eight runs on Sept. 1. In three starts since, he is 2-0 with a 2.50 ERA.
He felt "a little out of sync" early in Wednesday's start against the Dodgers, which came on seven days' rest, but wound up going six innings and giving up one run.
"The last three innings, I was much better," Zimmermann said. "I was able to control everything. It's definitely good to get a win. The infield did a good job, played great defense."
Brewers: Pushing through the pain
Left fielder Ryan Braun and first baseman Corey Hart both were in Sunday's lineup despite dealing with injuries to the groin and left arch, respectively. Both produced, going a combined 3-for-6 with three walks, a double and an RBI.
"It's that time of the year," Roenicke said. "You want to get it done, and the guys are going out there every day. I think this happens a lot. September's a tough month with these guys, physically."
Logan Schafer went 2-for-2 with a double and an RBI on Sunday in his first big league start. The 26-year-old played center field in place of Carlos Gomez, who is dealing with injuries, although Gomez later replaced Schafer and went 2-for-3 with an RBI.
Nationals: A rare hiccup for Mattheus
Reliever Ryan Mattheus entered Sunday's game with a 2.49 ERA in 61 appearances. He had allowed a run in only four of 25 games since Aug. 1.
But Mattheus, thanks in part to a lack of help from his defense, surrendered three runs in an inning of work on Sunday to take the loss. It was only the fourth time this season the righty has given up multiple runs in an outing.
Despite Sunday's loss, the Nationals are 61-30 (.670) when both Ryan Zimmerman and Michael Morse are in the lineup. Washington is 31-30 (.508) when at least one is absent.
The Nationals lead the season series, 4-3.
Estrada pitched two games and started one against the Nationals last season, giving up one run in seven innings and striking out eight.
On July 28, Zimmermann held the Brewers to one run in six innings in a win at Miller Park.