These division leaders are meeting for the second straight weekend and Milwaukee (69-55) has taken four of five matchups, winning 6-3 on Friday and 3-2 on Saturday at Dodger Stadium.
Kershaw had won 11 straight decisions before allowing a two-run homer to Ryan Braun and a solo shot by Carlos Gomez on Saturday.
"We've played good ballgames against them," Roenicke said. "We feel like when we play good and we've had good pitching that good things are going to happen, and that's a good club and you can't mess around too much, you can't make mistakes."
The Brewers have moved within a half-game of the Dodgers (70-55) in the race for home-field advantage in a division series but a matchup between Haren (10-9, 4.50 ERA) and Peralta (14-7, 3.46) may not necessarily work to their advantage.
Haren is 2-0 with a 0.90 ERA in three career starts against Milwaukee with 23 strikeouts over 20 innings, though only one of those came in the last five years. Gomez is 0 for 3 against him while Haren has never faced Braun.
The right-hander has yielded three runs over 13 1-3 innings in winning consecutive starts after posting a 10.05 ERA in losing his previous five. He credited a talk with manager Don Mattingly on helping him turn things around.
"Going through a rut like I was, I was pretty much off the Internet and ESPN and MLB," Haren told MLB's official website. "There's no need to see any negative reinforcements. It was good to feel something positive from him."
Peralta's strong season has been a major reason for Milwaukee's success. He registered a 1.64 ERA during a five-start win streak before allowing three runs in 6 1-3 innings in Tuesday's 3-0 road loss to the Chicago Cubs.
The right-hander's career 8.22 ERA against the Dodgers is his second-worst against any club. That came in two starts last year in which Matt Kemp went 3 for 5 against him.
He'll get his first look at Yasiel Puig, who is 7 for 12 in his last three games and 4 for 8 with two RBIs in this series.
Dodgers slugger Adrian Gonzalez is 9 for 18 with two homers and five RBIs in the season series.
Southern California native Braun is a career .352 hitter at Dodger Stadium, although he has just three hits in 20 at-bats on this seven-game trip.
"Every win is important," Braun said. "We've got to do everything we can to win as many games as possible, win as many series as possible and it's intense so it's a lot of fun."
Another Brewer who hails from the area is Khris Davis, who is 1 for 8 in this series in his first career starts in this ballpark.