The Rockies have held their own against most National League West foes this season, but they've struggled against the D-backs. Colorado has four games left in the season series to turn that trend around, beginning with Sunday's series finale at Chase Field.
Arizona has won nine of the 15 meetings thus far this season, while the Rockies are 8-8 against the Dodgers, 12-7 against the Padres and 9-10 against the Giants.
Colorado righty Jhoulys Chacin will square off against Arizona righty Randall Delgado on Sunday, with the clubs having split the first two games. The D-backs and Rockies will have their final series from Sept. 20-22 at Coors Field.
Delgado struggled against the Dodgers in his last start, giving up four homers and lasting just 2 2/3 innings. He's allowed 1.8 homers per nine innings this year, which would be the worst ratio in baseball if he had enough innings to qualify.
"I have a lot of questions about it," Delgado said when asked what he thought the reason was for allowing so many homers. "I thought I figured it out a month ago, but now it's happening again."
Sunday will be his first appearance against the Rockies this year.
He'll be up against Chacin, who is searching for his 14th win. The righty held the Giants to one run on four hits while striking out five over seven innings in his last start.
Chacin has a road ERA of 2.10 this season. His ERA since the beginning of August is 2.24.
"He's putting together a great run, a great season," Rockies manager Walt Weiss said. "His two-seamer is real good. It's diving to the bottom of the zone, and his changeup has turned into a really good pitch for him. And he can throw a slider to righties. He's got all three working."
D-backs: Lots of guys getting looks
With September callups, Arizona has four shortstops currently with the club -- rookies Didi Gregorius and Chris Owings and veterans Willie Bloomquist and Cliff Pennington. Manager Kirk Gibson plans to give most of the time down the stretch to the youngsters.
Gregorius got the start Saturday, while Owings looks to get the nod on Sunday.
"We want to see what they can do," Gibson said. "We know what Willie and Penny can do. So we want to get these guys some experience. [General manager Kevin Towers] will just have to make some decisions as the offseason approaches."
Rockies: LeMahieu streaking
Infielder D.J. LeMahieu wasted no time extending his hitting streak on Saturday, singling to right field in the first inning to extend his run to 14 games.
It's the second-longest current streak in the Majors, behind the Nationals' Denard Span's 25-game stretch.
• Todd Helton is two homers away from tying Ralph Kiner (369) for 74th on baseball's all-time list.
• Sunday will be the Rockies' 12th game of a 15-game stretch against NL West opponents. They're 3-9 so far.
Joey Nowak is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.