DENVER -- Rockies right-hander Germán Márquez’s next step has been backward, his new twist a tailspin.

In five innings of Tuesday night’s 10-2 loss to the Nationals at Coors Field, Márquez absorbed seven runs and 10 hits, including home runs by Josh Bell and Juan Soto. In four starts since holding the Dodgers to one run and three hits in seven innings in his season debut on April 9, Márquez has lasted just 19 innings, given up 35 hits and been saddled with a 9.00 ERA.

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“I’ve been working so hard to fix the little things,” Márquez said.

Márquez is bewildered that he can’t execute the fastball strategy that he thought would take him from being a 2021 All-Star to an even-higher level.

“I’m going out there to give it my best to win the ballgame -- I don’t want those games,” Márquez said. “My concentration and focus are still the same. Things are not working.”

Manager Bud Black sifted through theories: “It’s partly mechanics. It’s partly probably some concentration. It’s probably not being overly aggressive as he needs to be.”

Could his well-meaning 2022 strategy be a problem? During the weekend, as he prepared for the Tuesday start that went so poorly, Márquez expressed some surprise at the poor turn his fortunes have taken.

“I have to be stronger, man, like the first game this season,” he said. “And I had a good Spring Training. I hadn’t had a good one before.”

Coming off his first All-Star Game trip last year, Márquez, 27, spent much of his offseason in Denver to train and tinker with his pitches in the problematic altitude.

Márquez built his career working below the strike zone and glove side -- with a two-seam sinking fastball and a slider outside to right-handed hitters. Throughout his career he has fielded suggestions that he should become a threat in the other direction -- tight to righties. So he bought in.

“A four-seamer could help me out with the two-seam,” Márquez said. "When I’m going inside for righties, it’s a lot of two-seamers. But I want to throw fastballs, four-seam, right on the belt. I feel like I can control it on both sides.

“Well, I’m working on it. But I’m missing my spot.”

Márquez’s weapon is not a pitch, but his mix. In the past, the four-seamer was a distraction from his ground-ball pitches, the two-seamer and the slider. Hitters whiffed at his knuckle-curve. This year, little has been consistent.

In his previous start, when he lasted just 3 2/3 innings and gave up seven hits and four runs at Philadelphia, he felt good about the slider, although he wasn’t consistent with it. The fastballs were walloped, and his curveballs he intended to “put on the plate” simply hung in the middle of the zone.

“All have to work at the same time,” Márquez said.

During the weekend, Black wondered if Márquez’s emphasis on the four-seamer is throwing everything out of whack.

“It isn’t like he’s experimenting,” Black said. “But for him to be the pitcher he can be, he’s probably trying to do a little bit too much too early. These improvements take time. They don’t happen in two weeks. And he’s probably the guy who suffered the most from a lack of six-week Spring Training.”

The fastball has been particularly problematic. Going into Tuesday, according to Statcast, hitters had a .382 batting average, a .588 slugging percentage and a 44 percent hard-hit rate on his four-seamer. His two-seamer was hit to the tune of a .389 average, .556 slugging percentage and 72 percent hard-hit rate.

But Márquez was not going to abandon the four-seamer, which he believes can get weak contact.

“I have to try it,” Márquez said. “Because it was my choice.”

On Tuesday, he was all over the place. He forced two double-play grounders, and had a decent slider and curve.

“I’ve seen him really good, and seen him worse than tonight,” Bell said.

Soto, one of the game’s top hitters, smacked a changeup that Márquez and Black thought was good. But an outside four-seamer to left-handed-swinging Bell ended up in the left-field seats for the Nats’ first three runs. Bell is 2-for-21 in his career vs. Márquez, but both are home runs.

Márquez also gave up a two-out, two-run single to Keibert Ruiz on a poorly located fastball.

In a quiet postgame moment, Márquez said he believes in his strategy but is puzzled that he can’t put either fastball where he wants.

“I don’t think I’ve had these problems before,” he said. “I’m going to keep working on keeping the ball down.”