The Nationals, who won their final two games against the Phillies, have a magic number of three to clinch the National League East. The Cardinals, meanwhile, left Houston on Wednesday with their lead for the second NL Wild Card spot still at 3 1/2 games.
Regardless of how long it takes for both teams' magic numbers to hit zero, Nationals manager Davey Johnson said there isn't necessarily any added pressure in the season's remaining games.
"They're all big games. The first game we played of the year is a big game," Johnson said. "I never try to get too upset or too giddy when you win a bunch ... 162 games is a long time, so you need to maintain an even keel."
It's easy for Johnson to remain calm, as he sends Edwin Jackson to the mound against the Cardinals, who the right-hander dominated the last time he faced them. Jackson held the Cardinals to one unearned run and struck out 10 in eight innings to earn the win on Aug. 30.
Johnson is also expected to rest many starters if the Nationals do clinch the NL East, as the Nats' skipper has stated he doesn't care about securing baseball's best record.
The Cardinals, winners of four of their last five, are hoping to be healthier than they were at the completion of their road trip. Third baseman David Freese (right ankle sprain) is questionable for the series opener, but was encouraged Wednesday after hitting off the tee and doing some light running.
Even if Freese is unable to go, Carlos Beltran will return after not starting Wednesday for mental and physical rest as his trying second half continues.
"He's putting so much on his shoulders right now," Cardinals manager Mike Matheny said of Beltran, who pinch-hit on Wednesday. "I believe Friday could be a day where he comes back and busts out and is right back to the normal Carlos Beltran that we saw for the majority of the season."
Nationals: LaRoche, Zimmerman near century mark
With two more RBIs, Adam LaRoche would become the third Nationals player with 100 RBIs in a season, joining Ryan Zimmerman (2006, '09) and Adam Dunn (2009-10). Zimmerman needs to drive in six more runs to post his third 100-RBI season.
Center fielder Bryce Harper, 19, is the first teenager in Major League history to hit at least 17 home runs and steal 17 bases in a season. His 21 homers by a teenager are only topped by Tony Conigliaro's 24 as a 19-year-old in 1964.
Cardinals: Wainwright on the hill
Adam Wainwright gets the ball on Friday, looking for his first win in a month. He's struggled his last five starts, posting a 6.41 ERA and .308 average against, a stretch that began Aug. 31 when the Nationals chased him after scoring six runs in 2 2/3 innings.
Freese has a seven-game hitting streak.
Cardinals catcher Yadier Molina is 7-for-10 with one home run in his career against Jackson.
The Cardinals finished 9-7 in a stretch were they played 13 of 16 on the road.
With both teams winning on Thursday, the Nationals' lead for the best record in baseball stayed at one game over the Reds.