Peralta will try to avert his third straight loss to visiting Chicago on Monday night while Jackson looks to avoid his fourth defeat versus Milwaukee this season.
The only battle left for the Brewers and Cubs is determining which team will finish at the bottom of the NL Central, a spot Chicago has occupied each of the last three seasons. Milwaukee enters this four-game series 2 1/2 games ahead of the last-place Cubs (63-86) and will be looking for its fourth win in five contests Monday.
Rookie Sean Halton hit a walk-off home run after the Brewers (65-83) rallied from a four-run deficit in a 6-5 win over Cincinnati on Sunday.
"As a kid growing up, I wanted to be a baseball player and a major leaguer," said Halton, who is 5 for 13 with two homers in his last four games. "That's the top of the mountain."
Peralta (9-15, 4.49 ERA) is one loss shy of tying Houston's Lucas Harrell for the major league lead. It hasn't been solely the right-hander's fault, with Milwaukee providing no runs of support in nine of his last 14 starts.
"It's sometimes hard, because you have to be pretty much, like, perfect," Peralta told the league's official website.
Since allowing a career-worst seven earned runs against Cincinnati on Aug. 18, Peralta has gone 1-2 with a 3.80 ERA over his last four outings.
He is 1-2 with a 3.86 ERA in four starts versus the Cubs, but he's given up 11 runs and 13 hits while receiving no runs of support in consecutive losses against them. Only six of those runs, however, have been earned thanks to four Milwaukee errors.
Anthony Rizzo and Starlin Castro homered off Peralta in Chicago's 6-1 win July 31 and are a combined 9 for 23 with three home runs and seven RBIs against him.
Rizzo is batting .346 with three homers and nine RBIs in his last 14 games versus the Brewers, while Castro went 4 for 10 to help the Cubs end a nine-game losing streak at Miller Park with consecutive wins there in late June.
Jackson (8-15, 4.76) opposed Peralta in that July meeting and earned the victory after giving up one run without a walk over eight innings. He had posted a 6.48 ERA with eight walks while dropping his first three starts this season against the Brewers.
After ending a six-start winless drought by allowing one run over seven innings in Tuesday's 9-1 victory at Cincinnati, the right-hander looks to win consecutive outings for the first time since winning three straight June 30-July 11.
Milwaukee catchers Jonathan Lucroy and Martin Maldonado are a combined 7 for 20 with a home run and eight RBIs against Jackson this year. Lucroy is also 9 for 24 with two homers and six RBIs lifetime in this matchup.
Rookie Caleb Gindl, who hit his fourth home run Sunday, has gone 10 for 24 against the Cubs.