They may, however, already be in by the time the game starts.
Set to conclude their road schedule, the NL Central-leading Cardinals go for a three-game sweep against the Brewers.
Matt Adams hit his second two-run homer in as many nights and Matt Carpenter broke Stan Musial's single-season team record for doubles by a left-handed batter as St. Louis (91-64) trimmed its magic number to clinch a playoff berth to one with Saturday's 7-2 victory.
"We don't shy away from the fact that anything you get to play after game 162 is special," manager Mike Matheny said.
While the Cardinals can clinch with a win Sunday, they can also secure a spot if Washington drops at least one game in its day-night doubleheader against Miami.
St. Louis remains two games ahead of second-place Pittsburgh for the division lead.
"The only thing on my mind is the division championship," said Carpenter, whose 54 doubles lead the majors. "If I can do my job to help us win, then all those individual things will take care of themselves."
The Cardinals have hit .342 with runners in scoring position while going 14-4 against Milwaukee (68-86) this year. They have clubbed 14 homers and averaged 6.9 runs in taking eight of nine at Miller Park.
St. Louis is scheduled to give the ball to Joe Kelly (9-4, 2.74 ERA), who is 9-1 with a 1.84 ERA in his last 12 starts. After allowing four runs over five innings in a 5-3 loss to Milwaukee on Sept. 12, Kelly threw five scoreless innings before exiting with a calf injury in Tuesday's 11-4 win at Colorado.
The right-hander, though, should be good to go.
"You don't want to go out there and not be 100 percent and mess it up worse," he told MLB's official website."There's two starts left, and if I ended up missing one, I'd have one before the playoffs. It's just something you don't want to be going into the playoffs with."
Kelly is 1-3 with a 4.91 ERA in seven games - four starts - versus Milwaukee. Norichika Aoki is 5 for 11 with two doubles against him.
The Brewers give the ball to Wily Peralta (10-15, 4.34), who has the second-most losses in the NL. The right-hander, though, allowed one unearned run in six innings to beat the Chicago Cubs 6-1 on Monday, improving to 2-1 with a 2.89 ERA in three starts this month.
"He scuffled off and on, but he made good pitches when he needed to," manager Ron Roenicke said. "It is really important that even when he doesn't have his best stuff that he can keep us in the game."
Peralta has been hit especially hard against St. Louis, posting an 8.44 ERA in losing each of his three starts in the series. Carpenter is 4 for 8 in their matchups, and Matt Holliday is 3 for 7 with a homer.
Adams, who has homered in four straight games versus Milwaukee, is 12 for 24 with 11 RBIs during a seven-game stretch in the series. He is batting .395 with five homers and 12 RBIs in his last 12 overall.