Chacin has pitched well against the Arizona Diamondbacks, and has predictably fared better on the road than at home this year as these NL West clubs finish a three-game set Sunday.Colorado's bullpen has posted a 10.02 ERA in its last five games at Arizona (74-73), surrendering 10 runs over 7 2/3 innings in the first two of this series. No Rockies starter has been able to get through the sixth inning in those contests.Chacin (13-8, 3.09 ERA) could be capable of changing that since he is 4-2 with a 2.71 ERA in 11 starts against the Diamondbacks, including 2-1 with a 1.78 ERA in four on the road.Colorado (68-81) certainly hopes he continues his success against Miguel Montero, who is 3 for 18 off Chacin but 6 for 8 with a three-run homer in this series. Chacin has limited Paul Goldschmidt to one hit in eight at-bats and Gerardo Parra to three in 21.The Rockies right-hander owns a 2.10 road ERA compared to his 3.81 mark at Coors Field. He turned in his fourth straight seven-inning stint Monday in San Francisco, allowing one run in a 3-2, 10-inning defeat."He's putting together a great run, a great season," manager Walt Weiss told the Rockies' official website. "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."The Diamondbacks evened this series Saturday with a 9-2 rout. Parra and Aaron Hill each drove in three runs and Montero scored twice as Arizona went 5 for 13 with runners in scoring position."We did good with guys in scoring position, we did scoring damage tonight, as we should do," manager Kirk Gibson said.Gibson plans to give shortstop Chris Owings, 5 for 17 this year, his fifth career start Sunday. Fellow rookie Didi Gregorius started the first two games of this series, with veteran infielders Willie Bloomquist and Cliff Pennington out of the lineup both times."We want to see what they can do," Gibson told the Diamondbacks' official website. "We know what Willie and Penny can do. So we want to get these guys some experience."Gibson will give the ball to Randall Delgado (4-6, 4.04), who has never faced Colorado. Delgado is 0-3 with a 5.31 ERA in seven outings since his last win Aug. 2 at Boston.The right-hander will get his first look at DJ LeMahieu, who is batting .379 with seven RBIs during a career-high 14-game hitting streak.Delgado will also likely face NL batting leader Michael Cuddyer, who went 0 for 4 on Saturday to lower his mark to .332. Cuddyer batted .465 over his previous 11 games.Colorado's Todd Helton, who officially announced Saturday night that he will retire after this season, will play for the final time at Chase Field. Helton's 226 games against Arizona are the most all-time.