When the Colorado Rockies were competing for playoff positioning earlier in the season, one of the reasons they were in the hunt was their dominance over Arizona.
Colorado won eight straight over the Diamondbacks from May 5 to June 20 and was 40-34 overall at the end of that stretch, the high-water mark of its season. Now the Rockies are trying to get back to .500 after a 13-32 stretch that included a three-game sweep by Arizona in early July.
The Diamondbacks continued their winning ways against Colorado in the opener of a three-game series on Monday in Denver. Arizona trailed 4-0 in the first inning but used a big sixth inning to rally for an 8-6 win.
The Rockies have lost six of their past seven. Colorado fell 9 1/2 games back in the NL wild-card race while the Diamondbacks moved within 2 1/2 of the idle St. Louis Cardinals for the league's last playoff spot.
Jon Gray (10-8, 4.06 ERA) will be on the mound for the Rockies on Tuesday, trying to bounce back from a tough outing at San Diego on Thursday. The right-hander allowed seven runs but only three earned in 5 2/3 innings during an 8-3 loss.
Gray is slated to make his 11th career start against Arizona and his sixth at Coors Field. He is 3-4 with a 4.77 ERA overall against the Diamondbacks, including a 1-1 record in two starts this season.
Gray has become one of the more reliable starters for a rotation that has struggled this season, but the blame for the six-week swoon hits all areas. When the team has gotten good starts, the offense has gone quiet or the bullpen has been unable to hold leads.
"I think our team is better than what our record indicates, but I don't think we're as good as some of these really good teams," Rockies All-Star third baseman Nolan Arenado said before Monday's game. "As a group, we haven't really put it together. I always felt like we were going to. Obviously, we haven't. That's a sign it wasn't meant to be, I guess. There are still a lot of games left."
The Diamondbacks are still in contention for the postseason despite trading ace Zack Greinke two weeks ago, but they haven't had outfielder David Peralta in the starting lineup for the past two games after he developed neck pain Saturday night in a road loss to the Los Angeles Dodgers. He did pinch-hit in the sixth inning on Monday night, grounding out to second base.
"David is nursing a stiff neck," Arizona manager Torey Lovullo said before Monday's game. "Just through that right now. He did it on the last at-bat against Kenley (Jensen) on Saturday night."
The Diamondbacks will send rookie right-hander Zac Gallen (2-3, 2.40 ERA) to the mound Tuesday. Gallen, acquired from Miami on July 31, won his Arizona debut Wednesday with five shutout innings during a 6-1 win over the Philadelphia Phillies.
He is making his first career start and appearance against Colorado.
--Field Level Media