CLEVELAND -- When Coby Mayo was an elementary school-aged child in Coral Springs, Fla., he had hopes of growing up to be a professional baseball player, much like plenty of kids that age. For many, such a dream never becomes anything more than just that.

But for Mayo, now 22, his lifelong objective came true when he arrived at Progressive Field on Friday afternoon and walked in as a freshly minted big leaguer.

“Surreal,” Mayo said. “Driving in today, seeing the ballpark, I was like, ‘Gosh, this looks nothing like a Minor League park.’”

The Orioles selected Mayo’s contract from Triple-A Norfolk on Friday and inserted the third baseman into the No. 8 spot in their lineup ahead of their 8-4 loss to the Guardians at Progressive Field. It was the first big league callup for the 2020 fourth-round Draft pick, who had been patiently waiting for this moment.

“I was talking to my girlfriend [Ashtyn] this morning [about] being in first grade and writing that I wanted to play in the Major Leagues, and it’s a reality now,” said Mayo, Baltimore’s No. 3 prospect and MLB Pipeline’s No. 15 overall. “The moment I step on that field and the game starts is when the dream comes true.”

Although Mayo didn’t notch his first hit during an 0-for-2 showing, he drew a pair of walks -- one in his first plate appearance in the second inning and another in the seventh, when he later scored a run on a Colton Cowser single. Mayo also worked the count full before getting struck out by Cleveland closer Emmanuel Clase in the ninth.

The timing for Mayo’s debut wasn’t surprising. The O’s lost All-Star infielder Jordan Westburg to a right hand fracture -- which could sideline him until late in the regular season -- and Mayo is also a right-handed-hitting primary third baseman, so he can attempt to fill that hole.

Manager Brandon Hyde said Mayo will be playing at third “quite a bit,” as the Orioles make a push for their second consecutive American League East title over the final two months.

Westburg’s absence will be felt, but Mayo has the potential to provide a substantial boost. He’s had a tremendous season in Norfolk, where he slashed .301/.375/.586 with 22 doubles, two triples, 20 home runs and 61 RBIs in 77 games.

“He’s been killing it, and the numbers don’t lie, what he’s been doing and has been doing his whole Minor League career,” said Jackson Holliday, MLB Pipeline’s No. 1 overall prospect who went 2-for-3 with an RBI on Friday for his first career multihit game. “It’s awesome to have him here, and I’m really excited for him.”

Mayo’s promotion came two days after Holliday was called up to the big leagues for the second time. The youngsters spent much of the season together in Norfolk, where they talked about one day becoming Major League teammates.

On Friday, Mayo and Holliday (the 2022 No. 1 overall Draft pick) were eighth and ninth in Baltimore’s lineup, respectively, and in the same infield with shortstop Gunnar Henderson (‘19 second-round Draft pick) and first baseman Ryan Mountcastle (‘15 first-round Draft pick).

“I think it’s been at least in the top of my mind since [Holliday] got the first opportunity,” Mayo said. “I want to be up there with him and play with him, because he’s a special player, a really good teammate, someone I can always rely on to talk to about hitting and fielding and just outside of baseball life.”

Mayo isn’t the first prospect to join the Orioles this week, and he also wasn’t the first to debut in Cleveland in recent years. Henderson played his first MLB game at the same ballpark on Aug. 31, 2022, when he homered in his second plate appearance.

What advice does Henderson now give when he sees youngsters such as Mayo arrive?

“Obviously, just enjoy the experience,” Henderson said. “It’s kind of hard to in the moment, because you’re just wanting to play well. But you only get to debut once, so really just soak in the moment and try to make the most of it.”

Mayo found out he’d be getting called up shortly after he was removed from Norfolk’s game at Charlotte in the eighth inning on Thursday night. He was called into manager Buck Britton’s office and, at first, he thought the reason he’d been pulled was just to get him off his feet late in the contest.

Then, Britton broke a slew of news: Mayo was heading to Cleveland, getting called up by the Orioles and starting at third base for his Friday debut.

“I had the chills then, and I have them right now,” Mayo said. “A really special moment. Can’t really put it into words.”

As Mayo was learning this, his phone was already blowing up in his pocket. The news had broken on social media, and Mayo’s family was trying to get in touch with him to find out if what they were reading was true.

“The minute I FaceTimed my family in the group chat, I couldn’t even tell them, they already knew. They were just screaming. A really special moment,” Mayo said. “I think they’ve been waiting for that for a while.”

So have Orioles fans -- who have clamored for the slugger to get his chance all summer -- as well as Mayo himself.

But Mayo never got discouraged during his time in the Minors. He continued to put in his work, go out and rake in games, improve on his defense and wait his turn.

Now, it has finally arrived.

“This team has been in first place all year long, so why would you change something that’s working really well? They have a really good roster,” Mayo said of his wait. “I completely understand all of that, and I’m just really happy that I’m here right now.”