PORT ST. LUCIE — Tylor Megill arrived at spring training “on a mission” and will leave with a spot in the Mets starting rotation.

Manager Carlos Mendoza officially announced on Sunday that right-hander Megill will be part of the rotation for the upcoming season. Megill impressed during the Grapefruit League by demonstrating good control of his pitches and limiting walks. He is set to make his season debut in Game 2 against Houston.

Griffin Canning was also named to the rotation as the starter for Game 3 in Houston.

Clay Holmes will start Thursday’s season opener, with David Peterson and Kodai Senga set to pitch in succession next week in Miami.

Paul Blackburn will open the season in the bullpen, as The Post first reported was a consideration.

Mendoza highlighted that the decision was tough due to the strong performances of all pitchers. However, Megill stood out and earned his spot through his dedication and focus during spring training. He excelled in meeting the team’s expectations by throwing strikes, attacking hitters, and showcasing his elite pitching skills.

Canning, who arrived on a one-year contract worth $4.25 million, was projected from the start of camp to begin the season in the rotation.

In a final spring tuneup on Sunday, he held the Marlins to two earned runs over 4 ¹/₃ innings.

He finished the spring with a 1.88 ERA.

Despite having the option to return to Triple-A Syracuse, Megill emerged as a front-runner for the Mets’ starting rotation, especially with injuries sidelining other pitchers like Frankie Montas and Sean Manaea. His impressive display throughout spring training solidified his position in the team.

Montas has a high-grade lat strain that could cost him at least one-third of the season and Manaea is dealing with a strained oblique that will likely sideline him into late April.

Megill struggled early last season for the Mets and spent much of the summer at Syracuse.

But he returned to the major leagues in late August and pitched to a 2.32 ERA over his final six starts.

“Just attacking the strike zone and limiting walks,” Megill said of his late-season surge. “The big thing early on was I was walking a lot of guys and the pitch count got up. … If I can limit walks and those three-ball counts, I will be in good shape pitch count-wise and health-wise going into each inning.”

Blackburn will be used in a multi-inning relief role, according to Mendoza, to keep his pitch count extended.

The right-hander could be utilized as a starter beginning in mid-April, when the Mets are expected to begin employing a six-man rotation.

Blackburn underwent offseason surgery for a cerebrospinal fluid leak.

“I feel that I came with a lot of unknowns given the circumstances, with how the season ended last year,” Blackburn said. “Where I am now is where I feel I have always been toward the end of spring training, where I feel I am in good shape, good form to start the year and be ready to go.”

How would Mendoza characterize his starting rotation?

“I feel really good about it,” he said. “We are talking about guys with stuff, we are talking about guys with a lot of different pitch types, with Peterson. There is a lot to like. We feel very comfortable.”