ARLINGTON -- Dane Dunning has been one of the Rangers' better pitchers in 2021, but his first-inning struggles have been a blemish in his rookie season.

That trend continued on Saturday, as he gave up four runs in the first inning of Texas’ 6-5 loss to the Astros at Minute Maid Park. Dunning walked the leadoff batter before giving up three straight singles. The inning was capped by a two-run homer from Carlos Correa, the first home run that Dunning had surrendered since his first start of the season on April 6.

“Pretty much every starting pitcher, they're most vulnerable in the first inning,” said manager Chris Woodward. “We’ve talked about that as an offense ... that's when [pitchers are] kind of getting a feel for the game. If you get things rolling on a pitcher in the beginning, it stresses them out a little bit. They don't have their command. That's when you can take advantage. Sometimes you could score two or three runs before they even get settled.”

Dunning’s numbers confirm that he has struggled in the first more than any other frame. Here's his ERA broken down by inning:

1st: 10.12
2nd: 0.00
3rd: 7.04
4th: 0.00
5th: 3.60

Dunning said throughout his college and Minor League career, the first inning has typically been one of his better frames. He thinks teams have established that he’s a primarily sinker/slider pitcher and they’ve centered their game plans on that. He thinks he needs to get a better feel for the zone early in games and work a variety of pitches on the corners.

When he faces the Yankees on Thursday, Dunning wants to attack hitters more aggressively early in the game in order to work through the first-inning woes.

“Early on, for the most part, I usually try to work two pitches one time through the order,” Dunning explained. “And the second time through the order, I add another pitch in and kind of keep doing that the same, just because I'm not trying to show them all my pitches at the very beginning.

“I think it got to a point now where I need to start utilizing the changeup a little bit more, just to get hitters off the slider and off my sinker constantly. I think that’ll make my sinker and slider play at a higher percentage than normal.”

Woodward emphasized in Spring Training that he wants his starters to come out hot every night instead of easing into games. Dunning has seemingly struggled with that and appears to turn on the engine in the second inning and beyond.

Woodward said he’s not worried about those struggles long term, and Dunning is actively working to get better.

“He knows how to go out there and execute,” Woodward said. “He's not scared of anybody. Even after he's got a couple of rough first innings where you see most young guys crumble, he keeps going and keeps attacking. Did he make mistakes? Yeah. He put some balls in the middle of the plate that they hit, but he never backed down. I think that that's really good to see from a younger player.”

Through eight starts this season, Dunning has posted a 2-3 record with a 4.34 ERA and a 1.42 WHIP. Dunning has already walked more batters in May (8) than he did in all of April (5), but his 13 walks are on pace with past seasons in the Minors as well as his one previous MLB season in 2020.

Dunning -- the main return in the Lance Lynn trade with the White Sox this past offseason -- entered the 2021 season as the Rangers' No. 3 prospect before graduating from that status. Pitching coach Brendan Sagara said Dunning has shown many indicators that he could be a top-of-the-rotation guy down the road.

“It's just his first full season back from Tommy John [in 2019],” Sagara said. “So he's still making some adjustments and kind of getting back to the way his body moves down the slope, and kind of feeling those things out.

“But he can be [a top-of-the-rotation guy] with his command in the strike zone, ability to get outs in the strike zone and a kind of ground-ball focus. He’s a guy that has pitch efficiency built into his DNA, and obviously has the presence of a finishing pitch with the slider.”

Dunning said he’s learned a lot with each start he’s made this season and he’s fortune to learn from veterans like Kyle Gibson and Jordan Lyles.

“I think I'm headed on the right track, just like recognizing certain things of my pitches and my usage and stuff like that,” Dunning said. “Overall it's just execution during the game that I think I need to get better at, executing certain pitches during the game. And I feel like that's what comes in time and with each outing.”

Sagara said that next offseason and next spring, the pitching staff hopes to work with Dunning on diversifying his attack, but everybody is already pleased with his growth so far this season.

Woodward emphasized Sagara’s point and said that Dunning has been open to dialogue with the pitching coaches.

“I've said this before, but on the mound, he's a super-competitive kid,” Woodward said. “I love what he represents when he's in competition. He can think clearly and talk clearly about the game. After the game, he's not afraid to talk about it and not afraid to be critical of himself and figure out what he can do to do better. He loves talking baseball, so this kid's gonna grow faster than most because of that.”