PORT ST. LUCIE, Fla. -- Although the Mets won¡¯t finalize their Opening Day roster until later this week, much of it is already clear. That includes a rotation that has taken firm shape over the past few days.

While there aren¡¯t any surprises in terms of personnel, the rotation order looks a bit different than most might have expected heading into the year. Here¡¯s a look at how manager Buck Showalter and pitching coach Jeremy Hefner have drawn it up, complete with their reasons why:

No. 1: Max Scherzer
First start: Thursday @ Miami

No surprise here, as the Mets selected Scherzer to anchor their rotation and make his seventh career Opening Day start. Showalter said he could have picked out of a hat to choose between Scherzer and Verlander, but it made sense to go with Scherzer considering both his abilities and clubhouse standing. As the incumbent rotation ace in Flushing, Scherzer was a no-brainer to start Opening Day.

¡°It¡¯s a heck of a day to pitch on,¡± Scherzer said. ¡°The atmospheres are crazy every single venue that you¡¯re in. It¡¯s going to be a great day, and it¡¯s really fun to be out there and get the ball in that situation.¡±

No. 2: David Peterson
First start: Friday @ Miami

After Peterson capped his strong spring with five innings in a Minor League game on Saturday against the Cardinals, the Mets informed him that he won a rotation job over Tylor Megill. Although Mets officials think highly of Megill, Peterson outperformed him in Spring Training and has a longer track record as a Major League starter. The team figures to make his rotation spot official in the coming days. (Club officials did discuss the possibility of a six-man rotation to open the season, but that doesn¡¯t appear to be happening.)

"A lot of it just came down to feeling like I was in a good spot with all the pitches, mechanics, really feeling like by the end of Spring Training, I was in a really good spot built up to start the season," Peterson said.

What¡¯s unusual is that Peterson, the Mets¡¯ fifth starter in spirit, will pitch the second game of the season. More on those reasons below.

No. 3: Justin Verlander
First start: Saturday @ Miami

Considering Verlander was in contention for an Opening Day start, it doesn¡¯t make apparent sense for the Mets to have him pitch the third game. But multiple factors are at play here. One is that the club wanted to give Verlander the honor of pitching the home opener at Citi Field five days after his debut. The Mets also didn¡¯t want to stress Kodai Senga with the home opener assignment, considering it will be Senga¡¯s first time pitching in New York.

"It's such an honor," Verlander said of the home opener. "It's something I'm very much looking forward to, to introduce myself to the Mets fans."

More importantly, the Mets wanted to split up Scherzer and Verlander in the rotation. Even though those two feature divergent repertoires, they are similar enough that it could help them to have the lefty Peterson sandwiched in the middle. It can also aid the bullpen, which typically counts on longer outings from Scherzer and Verlander. Lining up pitchers this way helps ensure that Showalter won¡¯t often need to tax his relief corps on three consecutive nights.

No. 4: Kodai Senga
First start: April 2 @ Miami

One other factor went into the Mets placing Senga fourth in the rotation. Midway through camp, he was diagnosed with tendinitis near the base of his right index finger -- likely the result of squeezing the larger, slicker American baseballs too tightly. Senga wound up being fine after a brief period of rest, and team officials don¡¯t believe the issue will linger with him into the season. But there was little harm in giving Senga an extra day or two to start the season just to be sure.

Since returning from the injury, Senga has refrained from throwing his signature ¡°ghost fork¡± splitter to reduce the stress on his finger. He recently spoke to former Major League All-Star Koji Uehara, who assured him such discomforts are normal during the transition from Japan to the United States. Senga plans on unleashing his splitter again on Monday during his final spring tune-up in an intrasquad game.

No. 5: Carlos Carrasco
First start: April 3 @ Milwaukee

Much like Senga, Carrasco dealt with some discomfort midway through camp, skipping a start due to what Showalter called routine ¡°elbow maintenance.¡± The veteran right-hander will return to the mound on Tuesday in a Minor League game, before debuting on the fifth day of the season.

Entering camp, Carrasco was nominally the Mets¡¯ fifth starter anyway behind Scherzer, Verlander, Senga and Jos¨¦ Quintana, who will miss the first three months of the season due to rib surgery. Given Carrasco¡¯s elbow trouble, there was no reason for the Mets to shift him forward in light of Quintana¡¯s injury.