PHILADELPHIA — Just the day before, Kodai Senga was throwing in Florida, questioning whether he was putting his energy into recovering for a game that might not take place.

The very next day, Pete Alonso hits a dramatic three-run homer in Milwaukee, keeping the New York Mets’ surprising season alive, and Senga is on a plane heading to Philadelphia for what is potentially one of the most unexpected starts in Major League Baseball postseason history.

Despite pitching only once during the entire season, for a total of 5⅓ innings on July 26, Senga is set to start Saturday afternoon against the formidable Phillies in Game 1 of the National League Division Series.

No kidding.

This unexpected decision brings to mind the Chicago Cubs’ 2016 season when outfielder Kyle Schwarber missed the entire regular season due to knee surgery, only to return in time for the World Series as a designated hitter.

So, how many pitches can he realistically manage in the initial postseason game between these two National League East rivals?

“I’m prepared for anything,” Senga mentioned. “If they tell me to pitch 10 pitches, I’m ready for that. If they ask for 200, I’ll handle that too.”

Wait, when did you ever throw 200 pitches?

“Five years ago,” Senga replied, not even cracking a smile—pitch counts aren’t a big deal in Japan.

Mets manager Carlos Mendoza played it down when asked about Senga’s expected performance, admitting he also isn’t sure how long Senga will last.

“We’ll see; we’re going to let it unfold,” Mendoza said. “We have a strategy, but we will be monitoring him closely as the game progresses.”

In the end, it might be up to Senga himself.

He was the one who let the Mets know that he felt fit enough to join the team after missing the first four months due to a strained right shoulder, and then sitting out the last two months with a calf injury.

If he feels good and free of pain, he might continue pitching until he tells Mendoza to pull him out.

“No one understands him better than Kodai Senga,” Mendoza stated. “We’ve been with him all year. He always communicates with us when he doesn’t feel right, and that wasn’t the case this time. He reached out to us to inquire about our plans for the Division Series and potential NLCS.”

“We wanted to know his thoughts. He’s excited. He mentioned right away that he was ready.”

Senga has been a source of frustration for the Mets all season as they waited for him to return. In his only start back against Atlanta, he pitched into the sixth inning and struck out nine batters before gingerly leaving the field.

After that, he spent the summer rehabilitating, with his last known appearance being a bullpen session against Mets’ minor leaguers on Monday at their Port St. Lucie, Fla., facility.

He understood the Mets were counting on him and finally informed the team on Wednesday that he was ready to contribute in the playoffs.

Then Alonso delivered the game-changing homer, the Mets advanced, and Senga was en route to Philadelphia.

“I think it’s just that they’ve been very upfront with me,” Senga said. “They said, ‘Whenever you’re ready, we’d love to use you.’ I was able to prepare myself physically and mentally for this moment, and they fit me into the lineup.”

“I feel good physically. It’s about instinct. But I feel prepared now.”

The Mets were uncertain if they’d even make the postseason until they defeated Atlanta in a makeup game on Monday. They endured a tough best-of-three series against the Milwaukee Brewers, relying on Alonso’s clutch hitting, and could surely benefit from Senga’s return to strengthen their exhausted rotation.

However, some teammates might have doubted that Senga would actually be part of the plan, with a few having resigned to the idea he was out for the season.

“I was taken aback,” said Mets starter David Peterson, who was instrumental during Senga’s absence, finishing the season with a 10-3 record and a 2.90 ERA. “We hadn’t discussed it much. Everyone is thrilled to have him back, especially considering how the earlier part of the season went.”

“It’s exciting to have him back; he’s another top-notch arm at our disposal, and I can’t wait to see him compete.”

Still, it’s a fact that Senga will have thrown less than six innings over the last 374 days when he steps onto the mound at Citizens Bank Park in front of an enthusiastic sellout crowd.

“Just coming back in such an intense atmosphere, getting back to game speed,” Peterson noted, “will be a challenge when you’re coming back like this. Yet, I have complete faith in the work he’s put in and his readiness for this challenge.”

The Mets admit they are unsure of what to expect from Senga, but considering he dominated a strong Atlanta lineup during his only start in July, perhaps history could repeat itself at such a significant moment in his MLB career.

“This is no small feat, especially when he’s pitching against the Phillies,”

“Game 1 of the Division Series,” Mendoza remarked. “However, having not watched him all season and then stepping up against that Braves lineup was quite remarkable. We’ll see how he performs, and we’ll be ready to make adjustments if needed.”

Clearly, Senga is aware that the Mets have complete faith in him. If they doubted his readiness or believed he could only pitch for an inning or two, they wouldn’t waste an important roster position on him. You wouldn’t take a pitcher off your roster for the Division Series if you had serious concerns about Senga’s ability to deliver innings.

“The team has faith in me,” Senga stated. “I also believe in myself. All I can do is go out and give my best performance. I’m excited about it.”

It turned out very well for Schwarber and the Cubs in 2016, as they clinched their first World Series title in 108 years.

Given the Mets’ knack for stunning moments, why not a repeat?