DENVER -- The Reds played sloppy defense behind him and facing hitters at Coors Field can always be a gauntlet. But when Tyler Mahle added it all up Sunday afternoon following a 10-9 loss to the Rockies, the starting pitcher placed the blame on one person only:

Himself.

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“I don’t want to make excuses,” Mahle said. “I made a lot of bad pitches and mixed in with some bad luck, it turned into a really bad outing.”

Cincinnati (42-48) dropped two of three games in the series, plus four of its last five, and fell to 6 1/2 games behind the Cubs ahead of a pivotal three-game series that opens Monday at Wrigley Field.

Mahle pitched 4 1/3 innings with six of his 10 runs allowed being earned on a career-high 12 hits, with no walks and two strikeouts. It capped a rough two days for the rotation as Mahle and Tanner Roark combined to give up 25 hits.

The Reds aren’t looking to add starting pitchers ahead of the July 31 Trade Deadline, especially since their starting five entered the day with a 3.66 ERA that was ranked third in the National League and fourth in the Majors. The club also knows that if lefty Alex Wood can avoid a setback during his rehab assignment with Triple-A Louisville, it would be like adding a starter for a potential stretch run as Cincinnati tries to keep within striking distance. However, nothing can be assumed since Wood has yet to pitch in the big leagues since sustaining lower back spasms on Feb. 25.

Mahle will need some good starts quickly. He is 2-10 with a 4.82 ERA after 18 starts while the Reds have won just four of the games he’s pitched.

Just like in Saturday’s 17-9 Reds win, Colorado opened Sunday’s game with a 4-0 lead after the first inning. Following a leadoff double by Raimel Tapia, an error by third baseman Eugenio Suarez on Trevor Story’s grounder opened the gates for a big rally. Overall for the inning, Mahle gave up five hits -- all on two-strike pitches -- and four unearned runs.

But this being Coors Field, the Rockies’ lead was not safe as the Reds batted around in the top of the second inning and scored four runs off Antonio Senzatela to even the game. Cincinnati took a 5-4 lead in the fifth on Suarez’s sacrifice fly that scored Nick Senzel.

Mahle returned with a rough bottom of the fifth as the Rockies batted around again with seven hits and six runs scored.

“There were certainly some plays that we didn’t make today, for sure. Tyler came out struggling a little bit in the first,” Reds manager David Bell said. “He was good after that, until the fifth when they came out and were really super aggressive on the first pitch off of him.”

Story and David Dahl opened the Rockies’ fifth with first-pitch singles before Mahle’s failure to put away hitters with two strikes cost him some more. On an 0-2 fastball over the plate, Daniel Murphy hit a two-run double to right field for the go-ahead runs. Ryan McMahon hit a full-count curveball for an RBI triple to right field and Tony Wolters slashed a 1-2 fastball for an RBI single.

Some sloppy play followed as Senzel overran a Garrett Hampson single that allowed a run to score and moved Hampson to second base on the error -- the Reds’ third of the game.

“That’s what I’m most frustrated with. We take the lead and I go out and give it right back,” Mahle said. “Just bad pitches on 0-2, 1-2 [counts]. Pitches that shouldn’t be hittable and they were hitting them. Also, there was some bad luck. I’d jam a guy and he bloops one in. A couple of base hits were right down the line. But mostly, it was bad pitches.”

Bell was trying to avoid going to his bullpen early but soon had Matt Bowman warming up. But by the time Bowman was ready, the inning had already spiraled out of orbit on Mahle.

“We don’t play a lot of games here, but at some point, you have to allow guys to pitch a little bit too or you’re going to end up running through everybody too quick,” Bell said. “We got Bowman up and got him in as soon as we could get him ready. A lot of it happened quick, especially like there were a lot of first-pitch hits, ground-ball hits. Tyler was still throwing pretty good, but it did happen fast.”