After seeming to get back on track in his latest outing, Haren will try for a better performance versus the Arizona Diamondbacks on Saturday night.
Haren (6-4, 3.49 ERA) was 5-1 with a 2.84 ERA in his first eight starts before a 5-3 loss in Arizona on May 18. He was charged with five runs and matched a season high with 10 hits allowed in six innings.
Including that start, Haren was 0-3 with a 4.88 ERA in a four-start stretch before a 6-2 win in Cincinnati on Monday. He gave up two runs over 5 1-3 innings in his first win since May 12.
"I started the year throwing the ball very well," Haren said. "I've just really been mediocre here for a while."
Haren is 2-1 with a 4.26 ERA in three starts this year against the Diamondbacks, the team he pitched for from the start of the 2008 season until he was traded to the Los Angeles Angels on July 25, 2010. He benefited from a combined 15 runs of support in the two wins.
His former club has batted .226 while losing four of five but had 13 hits in Friday's series opener at Dodger Stadium. Los Angeles (36-33) managed to hang on for a 4-3 victory as Arizona (29-41) went 3 for 14 with runners in scoring position in its third consecutive defeat.
The Dodgers took the lead for good on Matt Kemp's two-run shot in the second inning - his first home run since May 10 - and avoided a season high-tying third straight loss.
''That was big for us,'' manager Don Mattingly said. ''We've struggled to score early and been getting behind a lot early here at home. It was good for us to get out to a lead.''
Mattingly's team has split its last six home contests after dropping three in a row and will try to earn back-to-back victories there for the first time since May 26-27 on Saturday.
The Dodgers will face Josh Collmenter (4-3, 3.65 ERA) in that attempt, and the Arizona right-hander will try to regain the dominant form he showed at the end of last month.
He was 3-0 with a 2.21 ERA in his final three starts in May, starting with a 5-3 home victory against Los Angeles on May 18, and capped that stretch with a three-hitter in a 4-0 win against Cincinnati on May 29.
Collmenter is 0-1 with a 5.25 ERA in two starts this month and gave up a combined four runs in the first two innings Monday against Houston. He followed with five scoreless innings in a 4-3 loss.
"He did his job. We had a great opportunity to come back and win. We just couldn't push them across," manager Kirk Gibson said. "He's had some good games where he's struggled early as well."
Collmenter gave up three runs and four hits in 5 1-3 innings in the matchup with the Dodgers in May and is 1-1 with a 5.56 ERA in two starts against Los Angeles this season.
Adrian Gonzalez is 3 for 5 with a home run and a double against Collmenter this season while Chris Owings is 7 for 8 with a double versus Haren. Owings is 9 for 11 with two doubles lifetime against Haren.
Arizona hasn't dropped four in a row since April 26-29 and hasn't lost four consecutive road games since April 19-22.