When Jackson Holliday arrived in Boston last week for his major league debut, he found his locker smack in a row with Colton Cowser, Jordan Westburg, Gunnar Henderson and Adley Rutschman.

If anyone was going to help him through his highly anticipated first game, it would be these guys. Henderson and Rutschman were both No. 1 prospects, while Cowser and Westburg ranked in the top 100. They understood the pressure.

“We’re just trying to keep him leveled,” Westburg said. “He’s so mature; he’s handled it really well.”

The four — no longer the youngest with Holliday in the picture — took the new guy under their wings. Cowser reminded Holliday to breathe. Westburg took a step back and let him do his thing. Henderson thought back to his own debut and reflected on what he wished he had been told.

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“I feel like I did a good job of soaking it in, but it’s hard to in the moment at some points because you want to play well so you have to lock in for that,” Henderson said. “Take everything in, don’t take anything for granted, because it only happens once.”

Holliday has struggled as he’s adjusted to the major leagues, going 1-for-25 with 14 strikeouts in seven games. He’s not the only one who has had trouble adapting to major league pitching, though. Cowser, Westburg, Henderson and Rutschman all had their moments when they first came up. Now, they are staples in the Orioles’ lineup. Just as Holliday will be one day.

How long a leash Holliday will be given remains to be seen. The Orioles let Henderson, Westburg and Rutschman figure things out in the majors, while they sent Cowser down to make adjustments.

Whatever the path will be for Holliday, here’s how Cowser, Westburg, Henderson and Rutschman got through the newbie slump.

Colton Cowser

Before he was this season’s phenom, Colton Cowser was last season’s struggling prospect in the big leagues. (Ulysses Muñoz/The Baltimore Banner)

When Cowser first came up last year, he fell behind in counts 0-2. Then, he almost overcorrected himself, becoming too aggressive and swinging too much. This year, he’s simplified his approach. He’s learned when to be patient and when to be aggressive, and it’s showing. He’s emerged as a left-handed power bat who can hit to the opposite side.

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Gunnar Henderson

Gunnar Henderson had a rocky start last season because he swung at too many pitches that would not have been called strikes. (Ulysses Muñoz/The Baltimore Banner)

Henderson had a decent first run at it, but his troubles came at the start of the 2023 season, when he was swinging and missing at pitches out of the strike zone. Henderson made adjustments, fixing his posture, leveling his shoulders and making minor tweaks in his setup.

Adley Rutschman

Adley Rutschman started his major league career in a slump. (Ulysses Muñoz/The Baltimore Banner)

Rutschman’s on-base percentage shot up quickly as he stopped swinging at balls and his plate discipline improved.

Jordan Westburg

Jordan Westburg has more home runs in 17 games than he did in 68 last season. (Jess Rapfogel/AP)

Westburg was steady when he first came up, but he’s even better this year. He’s comfortable at the major league level, showing power and taking advantage of pitches left over the middle of the plate. He has more home runs in 17 games than he did 68 last season.

Danielle Allentuck covers the Orioles for The Baltimore Banner. She previously reported on the Rockies for the Denver Gazette and general sports assignments for The New York Times as part of its fellowship program. A Maryland native, Danielle grew up in Montgomery County and graduated from Ithaca College.

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