PHILADELPHIA -- Until now, Kodai Senga's season has been an almost uninterrupted string of inaction. In the early days of Spring Training, Senga suffered a shoulder injury that was supposed to cost him a month or so. It ended up robbing him of far more time than that, keeping the right-hander shelved until July.

He has made just one Major League start since, and that was more than 10 weeks ago. But Senga is now ready to contribute at a crucial time. Mets manager Carlos Mendoza announced that Senga will start Game 1 of the National League Division Series against the Phillies at Citizens Bank Park on Saturday. It will be his second start of the year.

“We always had hopes, but it’s been the whole year,” Mendoza said. “What made us feel comfortable with this decision was that he was the one wanting the baseball.”

According to Mendoza, Senga approached Mets officials before the NL Wild Card Series Game 2, asking what their pitching plans would be if they advanced. For weeks, Mendoza had shrugged off questions about Senga, often outright laughing when asked about a potential timeline for the 2023 All-Star’s return. Senga’s idiosyncratic nature, combined with the deliberate pace of his rehab, made thoughts of a playoff start seem idealistic at best.

But as he spoke on the phone with Mets officials, Senga told them he was feeling physically strong enough to start. He came out of a 25-pitch live BP session earlier this week with no ill effects and he wanted to be part of the Mets’ postseason plans.

Because this was Senga asking for the baseball and not the team imploring him to take it, Mendoza believed the right-hander when he said he’d be ready.

“If anybody knows himself better than anybody, it’s Kodai Senga,” Mendoza said. “We’ve been through it the whole year with him. The times that he goes out there and faces hitters or throws a lot of bullpens and is not feeling right, he’s always letting us know that. And that wasn’t the case in this situation.”

Despite Senga’s long absence, the Mets have no qualms having him face one of the league’s top offenses in the Phillies, in part because of how electric the right-hander looked in his only other start. Back on July 26 at Citi Field, Senga held another strong offense in the Braves to two runs over 5 1/3 innings before badly straining his left calf.

The Mets won’t ask him to go nearly as long in this one. Although Mendoza declined to answer multiple times when asked about a pitch count or innings limit for Senga, the right-hander is not currently stretched out as a starter. As such, it’s unlikely he could contribute more than a couple of innings -- if he even lasts that deep in the game.

Per Mendoza, the Mets “have an idea, but we’re going to let the game unfold, and we’ll make adjustments as we go.”

“I'm ready for whatever,” Senga said through an interpreter. “If they say 10 pitches, I’m all in for 10 pitches. If they say 200, I’m in for 200.”

Last year, Senga was the Mets’ best pitcher, going 12-7 with a 2.98 ERA over 29 starts and making the NL All-Star team. He held the Phillies to two earned runs in two starts against them. Although this will be the first MLB postseason outing for Senga, he amassed plenty of playoff experience over 11 seasons with the Softbank Hawks in Japan.

The Mets have multiple options ready to go behind him, including starters David Peterson and Tylor Megill, plus their full complement of bullpen arms. Peterson closed out Wild Card Game 3, but he threw just eight pitches in the process. Megill wasn’t on the Wild Card roster and will be available for a full starter’s workload if needed.

These contingency plans are necessary because, in many ways, the Mets have no firm idea of what Senga can provide. Before this year, the only pitcher to start a postseason game after making no more than one MLB appearance in that season was Virgil Trucks, who started two World Series games for the 1945 Tigers after returning from World War II military service. Earlier this week, Atlanta’s AJ Smith-Shawver joined that list when he pitched for the Braves in NL Wild Card Series Game 1 against the Padres. Now, Senga will join it too.

In more ways than one, this start has been a long time coming for Senga, who signed a five-year, $75 million contract before last season. At his introductory press conference that winter, Senga was asked if there were any MLB hitters he was particularly looking forward to facing.

“Phillies lineup,” he responded in English.