It's been a bumpy ride for Dodgers right-hander Zack Greinke since returning from a broken left collarbone in May.
The right-hander began his comeback with a win against the Nationals on May 15, tossing 5 1/3 innings and allowing only one run on five hits.
However, he's been unable to record an out in the fifth inning in each of his past two outings. He went just four innings Monday against the Angels, allowing four earned runs on 10 hits and taking a no-decision.
He'll now try to get back on track Saturday, as the Dodgers face the Rockies at Coors Field.
It's also been a tough stretch for the Dodgers, who finished May with a 10-17 record after a gutsy 7-5 win over the Rockies in 10 innings on Friday.
"We're playing OK. Obviously not great, but not horrible," Dodgers manager Don Mattingly said. "We're treading water, and that's what we need to do right now. We're going to get hot as things start to fall into place. We've got to fight and not get discouraged just because we don't get on a roll. We need to tread water until we get people back."
Meanwhile, Jhoulys Chacin will be on the hill for Colorado, looking for his first win in more than a month.
The right-hander had a tough May, going 0-3 with a 5.87 ERA. In his last start Monday against the Astros, Chacin tossed seven innings and allowed just two runs on five hits, but took a no-decision.
Throwing only 82 pitches in the outing, Chacin also struck out a season-high nine and walked one.
"I feel pretty good about the performance," Chacin said afterward. "I feel like I could have gone longer, but it's not my decision."
Dodgers: Moylan added; Guerra optioned
• Veteran reliever Peter Moylan was promoted to the Dodgers' bullpen from Triple-A Albuquerque on Friday for their weekend series against the Rockies.
To make room for him on the 25-man roster, the Dodgers optioned Javy Guerra to Albuquerque. Room on the 40-man roster was made by transferring reliever Scott Elbert to the 60-day disabled list.
Moylan spent the first two months of the season at Albuquerque, where he was 2-1 with a 3.52 ERA. Moylan was limited to eight Major League games last year coming off shoulder surgery and signed a Minor League contract with the Dodgers.
Rockies: CarGo gets rest against Kershaw
• Left fielder Carlos Gonzalez was out of the Rockies lineup for Friday's series opener against the Dodgers.
Manager Walt Weiss said he recently decided Gonzalez could use a day off to catch his breath and Friday looked like a smart choice. Gonzalez, a left-handed batter, has hit just .227 in his career against Dodgers southpaw Clayton Kershaw, who started the series opener for Los Angeles.
"He's been playing well," Weiss said. "He's been grinding. It's been a long time since he had a day, so I felt like it was his time."
Gonzalez did pinch-hit in the seventh inning of Friday's game, striking out swinging against Kershaw.
• Hall of Fame former manager and Dodgers senior adviser Tommy Lasorda will be the guest speaker at the University of La Verne's spring commencement ceremony on Saturday.
• The Rockies lead the Majors with 44 stolen bases on the season.
Quinn Roberts is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.