Right-hander Kevin Correia will start for the Pirates, who lost to the Cubs, 13-9, Sunday to fall three games behind the Cardinals in the race for the second Wild Card spot.
Left-hander Travis Wood, coming off one of his best performances of the season, will be the Cubs starter.
Correia will be making his 25th start and carry a 10-9 record with a 4.29 ERA into the game.
Correia will be looking to bounce back after absorbing a 5-3 loss to the Reds Tuesday in a game in which he pitched six innings and allowed seven hits and four runs, three of them earned.
He struggled early, giving up a home run to Tony Phillips in the first inning, then allowed three runs in the second before settling down and finishing with four straight scoreless innings.
"A couple of random things happened in that second, and I gave up three runs," Correia said. "And that was pretty much the gist of the outing right there."
Wood has battled in his rookie season, compiling a 6-11 record with a 4.23 ERA in 22 starts and showed in his last outing Wednesday against the Astros why the Cubs like his potential.
The 25-year-old left-hander pitched 7 2/3 innings and gave up four hits and one run while striking out six in a 5-1 victory.
For the second straight start, Wood tossed four hitless innings to open the game.
"The ball's coming out good," Wood said after the game. "I've been able to locate pitches. I just want to finish the season strong and show them I can handle a full season."
Pirates: McDonald out of rotation
Right-hander Kyle McPherson will replace struggling James McDonald in the starting rotation and will start Wednesday's second game of the series.
McDonald has a second-half ERA of 5.84 in his past 12 starts, after going 9-3 with a 2.37 ERA in the first half.
McDonald said Friday he has lost his confidence.
Manager Clint Hurdle stressed he has not given up on McDonald and said the change might be beneficial to him.
"Sometimes the realization something's been taken away, maybe that can help him," Hurdle said. "A different kind of route as far as focus, as far as attention.
"He wants to do well, I don't think you could ever misconstrue that, but it's just growing up at the Major League level and finding yourself in a place where you can go out. You don't have to have your 'A' game every time. You can go out and compete. That focus has got to be there, that competitive nature's got to be there every time you get the ball. It's an honor to be a starter."
Cubs: Soriano closer to milestone
Alfonso Soriano, the Cubs's 36-year-old outfielder was 3-for-5 Sunday with two RBIs, raising his season total to 101.
Soriano also has 29 home runs and when he hits No. 30, he will be the fifth Cub, age 36 years or older, to reach 30 homers and 100 RBI in a season, joining Hank Sauer in 1954 (41 HR, 103 RBI, age 37), Andre Dawson in 1991 (31 HR, 104 RBI, age 36), Fred McGriff in 2002 (30 HR, 103 RBI, age 38) and Moises Alou in 2004 (39 HR, 106 RBI, age 37).
Manager Dale Sveum is a big fan of Soriano.
"Not too many 36 year olds have these kind of seasons," Sveum said. "He's having a heck of a year both defensively and offensively at a time when this team needed somebody to step up. Thank God he's stepped up and had one of his better seasons as a pro."
Younger players would do well to emulate Soriano, Sveum said.
"If everyone watched the way he goes about his business and does things every single day the same, his work ethic, the way he is in the clubhouse, he always has a smile on his face," Sveum said. "He goes out there with the knees he has, it should make all these young guys understand if they think they're hurting, try to play a game with what Soriano is going through every day with his knees.
"These are things that are invaluable to young players to look at a guy like that who is making $18 million a year and still busting his butt every single day and trying to make himself a better player as well as contributing."
Sunday was Cubs first baseman Anthoy Rizzo's first multi-homer game of his career. Rizzo homered twice, one a grand slam, and drove in six runs.
Pirates center fielder Andrew McCutchen had an RBI single in the second and reached base four times.
He has reached safely in nine of his last 11 plate appearances this series.