If the Yankees fall to the Red Sox and fail to complete the series comeback Thursday, it would not be because they were infiltrated by an outsider.

Cam Schlittler, raised just 20 miles from Fenway Park in Walpole, Mass., grew up immersed in Red Sox culture, attending Northeastern and supporting the team with his family. However, he has embraced a new identity as a Yankee and has even swayed his family to support the storied rivals.

“Being from Boston is something I take great pride in,” Schlittler remarked prior to his team securing a 4-3 victory in The Bronx, forcing a decisive Game 3. “But when it comes to my career aspirations, this is where I want to be. My family now fully supports the Yankees.

“They don’t wear it around as much in Boston just because. When they are here, they are very prideful about it.”

So his family will support a Boston kid trying to bury the Red Sox.

For the pivotal Game 3 of the wild-card round, the Yankees have chosen the formidable Schlittler, a 24-year-old who has already made 14 major league starts. The Red Sox, faced with an injured Lucas Giolito, will turn to rookie Connelly Early for the matchup.

If Yankees manager Aaron Boone pairs Schlittler with Ben Rice, it could be two Massachusetts boys trying to break the hearts of their childhood friends.

In his first 14 major league starts, Schlittler has never faced the Red Sox.

His Huskies did match up with them once, though. Back in February 2020, Schlittler — then a freshman at Northeastern — pitched in a spring training exhibition game at the Red Sox’s facility in Fort Myers, Fla.

“Great experience,” Schlittler said five years later. “Obviously I am a lot different player than I was then. So didn’t really expect to be in this situation back then, but now I am definitely happy I am.”

“This situation” is holding the season of his major league team and his childhood team in his right hand.

Called up in early July amid several injuries, most notably Clarke Schmidt requiring Tommy John surgery, Schlittler received an ostensible spot start that turned into a permanent rotation spot and a 2.96 ERA.

The Yankees moved on from Marcus Stroman, brought Ryan Yarbrough back from the injured list as a bullpen arm, did not further explore Allan Winans as rotation help and watched Schlittler’s ascension.

“You saw the right competitive edge to him,” Boone said of Schlittler, who burst onto the radar with a one-day, call-up to major league camp this spring and then excelled with Double-A Somerset and Triple-A Scranton/Wilkes-Barre. “Super coachable, accountable. I feel like he has done a really good job developing over the years.

“He has put together back-to-back, really impressive minor league seasons to earn his opportunity towards the end of the year. He gave us a shot in the arm when he became another stabilizing force in our rotation.”

That force is expecting “only a couple” immediate family members for the biggest game of his life.

They will be rooting for the Yankees.