Anthony Nunez had an idea.

It was already in Nunez’s head when the third baseman, released from pro ball but nonetheless playing in college, threw across the diamond for a scout at 100 mph. It proved out so quickly that, after his first college appearance on the mound, he had an offer to return to professional baseball.

He had an idea, his college coach said; he knew what he was doing. He had feel. He had a clue. He could pitch.

That was still true even when, after a spotless spring training, the Orioles sent him to minor league camp in mid-March. And they must have known it was, because Nunez was a surprise inclusion on the opening day roster just over two years after his debut on the mound. And, with two scoreless innings Saturday, one of the most improbable stories in baseball may only be getting started.

“It’s been a hell of a ride,” Nunez said this spring.

A native of Miami’s Hialeah neighborhood, Nunez was San Diego’s 29th-round pick in 2019 as a third baseman, but he only briefly made it to A-ball. He was released in 2021 with few enough games played to receive eligibility to return to college baseball at the Division II level, which he did at the University of Tampa.

Nunez hadn’t pitched since he was 10, but the idea stuck with him. When a scout came to watch practice in 2023 and asked his coach if there was anybody worth seeing, he mentioned Nunez might want to give pitching a shot. He asked Nunez to throw a couple of balls from third to first.

“I threw 100 [mph] across the infield,” Nunez said, “and that same day the scout said, ‘Start throwing bullpens.’”

He did later that season, starting slowly.

“There’s a process that goes along with it because you’ve got a guy that’s probably the best defensive third baseman we’ve ever had at Tampa and hit in the middle of our lineup, so we’ve got to be careful with how we do this,” Sam Militello, Tampa’s associate head coach, said.

They began with the basics. Given the team played on the weekends, the plan was for 10- or 15-pitch bullpen sessions during the week to get Nunez comfortable throwing fastballs off the mound and build the foundation of a delivery.

He always liked to hang out with the pitchers during batting practice when he wasn’t hitting and had learned a changeup from them, so that became an early weapon. Militello could tell by how he commanded it that there was something unique happening.

“He had a clue,” Militello said. There was a chance that, even without throwing in a game, Nunez might sign with a pro team as a pitcher after the 2023 season. He wanted to pitch a full season for Tampa first, and that fall, even though he was going to play third and hit in the heart of the order, the Spartans treated him like a pitcher. The plan was for him to close one game a weekend and, even before fall games started, it felt like it was working.

Militello said: “It’s coming out differently than most people and, again, he had an idea. He had a feel, which is what astonished me. You don’t take position players very often, put them on the mound and have them have an idea of what they’re doing.”

That fall they added a breaking ball to the mix, shifting it from a curveball to a slider that paired better with his fastball and was easier on his arm. By the time the season started, Militello said, he was their best arm. Even if there wasn’t a save situation, they’d give him an inning in the last game of the weekend to keep him on schedule.

That’s what happened during the season-opening tournament.

“The radar guns are everywhere, and it’s all of a sudden 97,” Millitello said. “We’re like, ‘Oh my God. This is real.’”

That was the first of 11 outings for Tampa that year, with Nunez striking out 20 in 11 2/3 innings — for the Division II national champions. He signed with the Mets as a free agent once the season ended, with the progressive pitching organization a good match for Nunez, who dove into the numbers.

“For me it’s huge, because when I have one feel and the shape looks really good, I can repeat that feel,” Nunez said. “It’s not chasing the metrics, but the metrics help me know what feel works and how I can repeat the same movement and the same execution for pitchers.”

That’s how he honed his four-seamer and changeup with the Mets, and changed his slider into a sweeper, and added a two-seam fastball, and this year added a cutter and tweaked his changeup into a kick change. It’s how he made a quick impression with the Mets, for whom he was carrying a 1.58 ERA and 0.80 WHIP with 60 strikeouts in 40 innings in the minors when he was part of the Orioles’ return in the trade that sent Cedric Mullins to New York.

It was then that Nunez’s path to the big leagues crystallized, for him at least. Because he signed his first minor league contract in 2019, the Orioles risked losing him for nothing this offseason if they didn’t add him to their major league roster. After he pitched well to end last year at Triple-A Norfolk, that was never a question.

He spent the winter training at Tampa Premier Sports with Nicole Gabriel, who led a daily group of big leaguers and watched Nunez spend as many as five hours a day working on his body and his craft, soaking up as much as he could from the more experienced players in the group. She said he made gains with focused training and progressed in finding an arm care routine, but through their baseline testing at the beginning of the offseason, she had an idea why Nunez has picked up pitching so fast.

“It’s almost like he was built for this, honestly,” she said. “He’s just genuinely built differently. … He’s just an athlete, a natural athlete, and I think just training him in the proper ways has really helped him.”

This is how, barely two years after taking the mound in a real game for the first time, Nunez earned his way onto the Orioles’ roster. This club has received unexpected bullpen contributions this decade from Félix Bautista, Yennier Cano and many more.

Nunez has the talent to join them.

“He’s always had a good arm,” said outfielder Enrique Bradfield Jr., who grew up playing with him in the Miami area. “Did I think he would become a really good pitcher? No, I didn’t. I don’t know that he expected it on his own, and I don’t know that anybody else saw it.”