JUPITER, Fla. -- Manager Carlos Mendoza made official on Wednesday what had been clear for weeks: Tylor Megill will be in the Mets’ Opening Day rotation.

Megill won the job in the wake of Kodai Senga’s injury, which will sideline the Mets’ ace at least until May. Mets officials informed Megill of the decision before Wednesday's 6-3 win over the Marlins while optioning the other top contender for the job, José Buttó, to Minor League camp.

“We’ve been saying that we were going to be facing some tough conversations, and this morning we had one with Buttó,” Mendoza said. “Not only because of the way he’s been throwing the ball, but how he prepares, the way he goes about his business, how good of a teammate [he is]. He basically did everything we asked him to do. That’s why it’s one of those where it was a tough one.”

Buttó allowed just one run over 10 innings in Grapefruit League play, flashing 97 mph on the radar gun. Megill produced a 3.45 mark over 15 2/3 innings, with much of that damage coming in his last outing.

Still, with Senga out, Megill quickly emerged as the obvious candidate to step into the rotation for three reasons. One was his overall longer body of work in the Majors, which matters more to team officials than the small sample size of spring statistics. Two was his performance down the stretch last season, when Megill produced a 2.55 ERA over his final six starts. Three was the quality of Megill’s stuff in Grapefruit League play, including a fastball that topped out at 97 mph and his continued development of a splitter.

“He showed up in really good shape,” Mendoza said. “He was already throwing live BPs -- like, credit to him. The way he approached his offseason and how he prepared … and then the outings, the way he threw the baseball, how he was bouncing back. This is a guy that’s done it. He has a little more experience than Buttó, and we decided to go that route.”

Although Megill is the fifth starter in title, he is unlikely to line up fifth in the rotation, according to those familiar with the team’s thinking. The reason is because the Mets want to avoid starting two left-handers, José Quintana -- who is starting Opening Day -- and Sean Manaea, against the Brewers during the opening series.

Instead, the Mets intend to use Megill for Game 3. (Mendoza has only announced the rotation through Game 2, which will be started by Luis Severino.)

Last season, Milwaukee ranked 26th in the Majors against right-handed pitching with a .695 OPS. Against lefties, they were 16th with a .731 OPS. If anything, the Brewers should be even more skewed this season after parting ways with lefties Rowdy Tellez and Jesse Winker, as well as switch-hitter Carlos Santana, over the offseason. Their most prominent newcomer is a right-handed hitter, Rhys Hoskins.

Manaea, who would make sense as the No. 3 starter on merit, features the most extreme left-right splits of any Mets starter. While Manaea held lefty hitters to a .200/.273/.297 slash line last season, neutralizing them with his slider and sweeper, righties mashed him for a .253/.327/.446 line. That makes him a better matchup against the Tigers, who come to town for the second series of the season.

As such, the season-opening rotation should look like this:

March 28 vs. MIL: Quintana
March 30 vs. MIL: Severino
March 31 vs. MIL: Megill
April 1 vs. DET: Manaea
April 2 vs. DET: Adrian Houser

After that, the Mets will proceed with a regular five-man rotation at least until April 10, the sixth game in a run of 13 consecutive games without an off day that would set them up to promote a sixth starter if they desire. Even with Senga on the sidelines, Mets officials like the idea of working in a sixth man on occasion to give everyone else an extra day of rest.

If Buttó is pitching well when the team makes that decision, he will be the obvious candidate to receive a quick call-up.

“That was part of the conversation: you’re going to go down there and just make that decision easier for us,” Mendoza said of Buttó. “He’s going to pitch a lot of innings for us. And he’s going to give us quality innings.”