DENVER -- The decision to take Michael Wacha out of Tuesday night’s game after four innings and two runs allowed came because of a bases-loaded situation for the Cardinals.

It just didn’t work out, and they lost, 2-1, to the Rockies at Coors Field.

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Trailing by a run in the top of the fifth, the Cardinals loaded the bases with a Rockies error and two singles. With only one out, Cardinals manager Mike Shildt pulled Wacha -- who had thrown 68 pitches and given up a first-inning, 482-foot home run to Nolan Arenado for the Rockies’ only runs of the game -- for pinch-hitter Matt Carpenter, who is a career .472 hitter with the bases loaded.

But Carpenter hit a popup with a 58.8-mph exit velocity, according to Statcast, to shortstop Trevor Story, and Dexter Fowler followed with a groundout to first base.

The Cardinals turned to relievers Ryan Helsley and Giovanny Gallegos for two innings each to finish out the series opener -- a move that Shildt said wouldn’t have come in a game at Coors Field without a deep bullpen that September rosters bring.

“[The decision] came down to a couple of things, really,” Shildt said. “Primarily the fact that we had the bases loaded and a really dangerous hitter in Matt Carpenter ready to take that at-bat. Coupled with the fact that we’ve got guys who are rested and we’re confident they can go out and throw well and keep us right there.

“That’s exactly what happened, we just weren’t able to to scratch any more across.”

The loss did not come back to bite the Cardinals, whose lead in the National League Central remained at four games following the second-place Cubs' defeat in San Diego on Tuesday.

It was not the start to the mid-week series at Coors Field that the Cardinals wanted. The Rockies are the final non-contending team that St. Louis will face this month -- with seven games against the Cubs still on the schedule. If anything, the Cardinals needed to storm into Denver and widen their lead to prepare for the upcoming challenge of the final weeks in September.

The series opener ended with six Cardinals hits and six left on base.

“Anytime you lose 2-1 in Colorado, it’s missed opportunities,” second baseman Kolten Wong said. “You ask anybody in this clubhouse, we all collectively had chances to do something and didn’t do it. It’s one of those where you definitely want to forget about it, come back tomorrow and try and get back on it.”

Just a few weeks after the Cardinals scored five runs in 4 1/3 innings off of Chi Chi Gonzalez in St. Louis, the right-hander held the Cardinals to four hits for his first win since Sept. 22, 2015, when he was a member of the Rangers.

“He was spotting up pretty well,” Wong said. “Aggressive. In St. Louis, he wasn’t as aggressive, but here he was able to locate that cutter backdoor really well against me. [Kept] that fastball in, where his fastball’s got a little pull cut. When you’re cutting it in and able to cut it back on, it makes it tough to get. He was on tonight. Hats off to him.”

When the Cardinals finally got Gonzalez out of the game after six innings, they had another opportunity in the seventh. Paul DeJong walked to lead off and stood on third with one out, but Bader struck out swinging and pinch-hitter Jose Martinez did the same to end the frame.

“I think all of them [hurt],” Shildt said. “We weren’t able to scratch any runs, especially when it’s a one-run game. We had a lot of opportunities. Just weren’t able to cash in.”