NEW YORK — Clay Holmes never saw himself as a reliever only, as the type of pitcher incapable of hacking it in a big league rotation. He didn’t feel that way when the Pirates transitioned him to the bullpen in 2018, nor when he became a standout closer for the Yankees. At one point, Holmes even considered signing overseas as a starter.

Somewhere in the back of his mind, Holmes always believed he could start.

So when the right-hander became a free agent last month, hitting the market just as the concept of relievers transitioning to rotations had come in vogue, he and his agent took advantage of the moment. They told teams that Holmes was interested in starting. Some, including the Mets, were intrigued.

That’s how Holmes came to sign a three-year, $38 million contract with the Mets, who formally introduced him Tuesday on a video conference. Wearing a pink “Meanwhile Back in Queens” T-shirt, Holmes offered optimism that he can not only transition to the rotation, but thrive there.

“I didn’t want to look back at the end of my career and say, ‘Man, what could have come from that?’” Holmes said. “It was something that deep down, I still had a passion for.

Whether this experiment works won’t be clear for months, but both Holmes and Mets officials believe the pieces are in place for a sound transition. Even before last season ended, Holmes began tinkering with a four-seam fastball in games and a changeup in bullpen sessions — two weapons that he plans to use regularly as a starter. Although Holmes still considers his upper-90s sinker his bread-and-butter pitch and intends to lean on it heavily, those extra options could come in handy against left-handed hitters.

Holmes will also reunite in Queens with Desi Druschel, an expert in pitch shaping whom the Mets hired away from the Yankees to be their assistant pitching coach. During the recruitment process, Holmes spoke at length with head pitching coach Jeremy Hefner, who guided him through what a transition could look like.

“There’s a lot of trust in what they’re able to do and what they see and how they’re able to develop starting pitchers and even do that in the big leagues,” Holmes said. “It just gave me a lot of confidence. It’s definitely not going to be a transition that just happens, that I can do by myself. And so surrounding myself with people that I felt really good about was important.”

Then there is the matter of precedent. Holmes intends to reach out to his former Yankees teammate Michael King, who moved to the rotation under similar circumstances in 2023 and finished seventh in National League Cy Young Award voting during his first year as a full-time starter. Others, such as Seth Lugo, Reynaldo López and Jordan Hicks, have successfully transitioned in recent years.

“When you see guys make the transition, it’s definitely like, ‘This is possible’ and ‘This is cool,’” Holmes said. “There’s definitely somewhat of a little road map, seeing how guys do it. It’s not super common, but you don’t feel like you’re in uncharted water.”