Mattson gets two outs vs. Red Sox in debut

May 8th, 2021

No matter if you're a future Hall of Famer or just getting a cup of coffee, you never forget your Major League debut. They are always unforgettable for the players making them, regardless of the outcome, context or circumstance. And sometimes they offer glimpses of greatness to come.

They are also the type of milestones in large supply lately for teams like the Orioles, who are prioritizing youth and are geared toward the future. This is why their 2021 season figures to be full of nights like Friday, when rookie right-hander Isaac Mattson debuted at the tail end of the O’s 6-2 loss to the Red Sox at Oriole Park at Camden Yards.

A little more than a month into the season, Mattson became the sixth Oriole to make his MLB debut in 2021 and the seventh rookie to appear for the club. More are likely to come throughout the season.

"When guys make their debuts and are in a Major League stadium for the first time, it's a really special feeling," manager Brandon Hyde said. "I'm sure their hearts are beating super fast."

Here is how they fared in those moments, along with a running list of all the O's debuts this year:

Isaac Mattson, RHP
Prospect ranking: Unranked
Debut date: May 7

Rarely does a player hear the news of his MLB promotion from his future big league manager, but Mattson did. The right-hander was informed he was heading to the Majors by Hyde while on the treadmill last week -- such is life on the MLB taxi squad circa 2021. A few days later, Mattson was summoned to record the final two outs of Baltimore’s eventual 6-2 loss to the Red Sox. He allowed one run on one hit and one walk, in the process becoming the first prospect acquired by Mike Elias to appear in the Majors. Mattson was part of the four-player haul in the Dylan Bundy trade in December 2019.

Jay Flaa, RHP
Prospect ranking: Unranked
Debut date: April 27

A sixth-round Draft pick in 2015 who spent parts of the past seven years in the Minors, Flaa became only the 20th player from North Dakota to pitch in the big leagues when he debuted in mop-up duty for the Orioles against the Yankees. The righty logged 1 1/3 innings of scoreless relief, walking two in the ninth but striking out Aaron Judge to escape his debut unscathed.

“Escape artist,” Hyde said. “When he got behind in the count, I was a little concerned!”

Said Flaa: “It was pretty surreal being out there. There were a lot of emotions building up to that.”

Zac Lowther, LHP
Prospect ranking: No. 11, per MLB Pipeline
Debut date: April 25

The O's second-round pick in 2017, Lowther enjoyed success at every Minor League level before the pandemic, and he performed well at their alternate training site and big league Spring Training in 2021. His debut went smoothly, allowing one hit and striking out one over a scoreless ninth. Lowther retired the heart of the A's red-hot lineup, striking out All-Star third baseman Matt Chapman to end the game. His bullpen days may be numbered, as Lowther is a candidate to start later in the summer.

"Very cool moment for him and a nice way to break him into the big leagues," Hyde said. "I was pumped to watch him on the mound, and he didn't disappoint -- threw strikes, showed multiple pitches, didn't look nervous, though I'm sure he was."

Mac Sceroler, RHP
Prospect ranking: Unranked
Debut date: April 5

One of two Rule 5 Draft picks to win a bullpen job out of Spring Training, Sceroler made the jump from Class A Advanced (in the Reds' system) to the Orioles' Opening Day roster. He was then thrown right into the fire, inheriting a bases-loaded, one-out sixth-inning jam from Paul Fry in Baltimore's 7-0 April 5 loss to the Yankees. His first batter? Aaron Judge, whose solo homer off Jorge López in the fourth inning provided the Yankees a lead they wouldn't give back.

Sceroler was unfazed, freezing Judge with a 3-2 fastball en route to escaping the jam unscathed, and retiring his first seven big league hitters overall.

“I could finally breathe,” Sceroler said afterward. “I knew I was still in the game so I couldn’t relax too much, but I could take a few minutes to process what just happened, breathe and then get back to competing out there.”

By the end of the outing, he'd logged 2 2/3 scoreless innings of mop-up relief, striking out four and walking two. Meanwhile, unknown to Sceroler, the Orioles' broadcast Zoomed with his uncle, former O's pitcher and current analyst Ben McDonald. The righty made one more appearance before landing on the 10-day injured list April 13 with shoulder tendinitis.

“To be put in a situation like that, that’s what everyone wants to be put in just to prove themselves,” Sceroler said. “To show I can pitch and get the job done. It was comforting for me, to be put in that situation and to succeed.”

Ryan McKenna, OF
Prospect ranking: No. 15
Debut date: April 5

The Orioles' fourth-round Draft pick in 2015, McKenna advanced to Double-A Bowie in '19 and spent most of '20 at the alternate training site, earning some late-season taxi-squad duty. He was called up from the taxi squad in place of the injured Austin Hays to provide outfield depth, and immediately thrust into the starting lineup to spell everyday right fielder Anthony Santander. McKenna then experienced a quiet debut, going hitless with a walk in three plate appearances. He was summoned again when Santander landed on the injured list in April 21, going 3-for-15 with five runs scored in his first 13 big league games.

Tyler Wells, RHP
Prospect ranking: Unranked
Debut date: April 4

The 6-foot-8 Wells reached Double-A in the Twins' system in 2018, but he missed the next two years recovering from Tommy John surgery by the time the Orioles selected him, along with Sceroler, in the Rule 5 Draft. The righty earned a bullpen role out of Spring Training and debuted in the O's 11-3 win over Boston, pitching a scoreless ninth inning to close out their third victory of the season. Wells allowed one hit and walked one in his debut, but he stranded both baserunners, flashing two distinct breaking balls in the process. He allowed six earned runs in 7 2/3 innings across five appearances as of April 26.