Dodgers’ Zack Greinke knocks down Rockies

Talk of the Dodgers having co-aces in Clayton Kershaw and Zack Greinke has been mostly just talk.

Kershaw has looked like an ace this season. Greinke, for the most part, hasn’t.

But that could be starting to change.

Greinke pitched his first shutout in three seasons, leading the Dodgers to their 17th victory in their last 21 games, a 1-0 victory over the Colorado Rockies on Saturday at Dodger Stadium.

BOX SCORE: Dodgers 1, Rockies 0

“It was pretty special today, what he did,” catcher A.J. Ellis said.

The fact that Greinke was similarly brilliant in his last start — he pitched seven scoreless innings in Arizona five days earlier — gave credence to Manager Don Mattingly’s theory that he just needed time to build his arm strength.

Greinke had a sore elbow late in spring training and fractured his collarbone in a bench-clearing incident with the San Diego Padres only two starts into the regular season.

Greinke didn’t give up his first hit Saturday until there was one out in the fifth inning. He gave up two hits the entire game and walked only one batter. He struck out nine.

If this was a preview of what is to come from Greinke after the All-Star break, what does that mean for the Dodgers?

Ellis smiled. Of the 1-2 punch of Kershaw and Greinke, Ellis said, “That’s like a two-headed monster. When those guys are pitching back to back, it’s going to be a long 48 hours for a lot of teams.”

Greinke improved to 8-2 and lowered his season earned-run average to 3.49. Kershaw is only 8-6, but leads the majors with a 1.98 earned-run average.

“Our guys behind them aren’t too bad, either,” Ellis said.

Greinke seconded that opinion, pointing to Hyun-Jin Ryu and the recently acquired Ricky Nolasco, who will pitch Sunday in the Dodgers’ last game before the All-Star break.

Ryu is 7-3 with a 3.09 ERA. Nolasco held the Diamondbacks to a run over seven innings in his first start with the Dodgers.

“Ryu, he’s had a couple starts not great, but, for the most part, he’s as lights out as anyone,” Greinke said. “And Ricky, the last game, if he pitches that good, people aren’t going to hit him. He was really good. That will be fun if people stay where we’re at right now.”

Greinke credits his recent improvement in form to some mechanical adjustments suggested to him by pitching coach Rick Honeycutt.

“Just more straight on,” Greinke said of pitching motion.

That has resulted in improved command, according to Greinke. He walked a career-high seven batters in Colorado on July 3. He has walked a combined three hitters in his last two starts.

Others also see more late life on his fastball — in Mattingly’s words, Greinke is now pitching “through the zone”; before he was pitching “to” it.

“The ball looks like it’s going to come to the bottom half of the zone or go low in the zone, but it stays up,” Ellis said. “There were a lot of pitches that they thought were down and they weren’t down. They stayed at the knees.”

The way Greinke pitched Saturday, it didn’t matter that the Dodgers were held to a run and four hits over eight innings by the Rockies’ Tyler Chatwood.

The Dodgers scored their only run in the first inning, when Skip Schumaker led off with a double, advanced to third base on a groundout by Adrian Gonzalez and scored on another groundout by Hanley Ramirez.

“Teams that score, score and score but don’t have pitching, it wears you out,” Mattingly said. “You can’t keep scoring like that. A win like this, it tells you don’t always have to score five or six.”

dylan.hernandez@latimes.com

twitter.com/dylanohernandez