NEW YORK — The Yankees were so confident in rookie righty Cam Schlittler that not only did they not add a starting pitcher at the trade deadline, they subtracted one. New York released veteran Marcus Stroman the day after the deadline and went all-in on Schlittler as their No. 5 starter the rest of the season and, potentially, into October.

Thursday night at Yankee Stadium, Schlittler rewarded the team’s faith and then some.

Thanks to Schlittler’s eight shutout innings, the Yankees are heading to Toronto for the ALDS after beating the Red Sox in Game 3 of the Wild Card Series (NYY 4, BOS 0). The Yankees are the first team since the 12-team postseason format was implemented in 2022 to come back to win the best-of-three Wild Card Series after dropping Game 1.

“Every time he has taken the ball, I feel so good about him that he’s capable of the play because he is such a good strike thrower and with that stuff,” Yankees manager Aaron Boone said after Game 3.

Schlittler, a seventh-round pick in 2022, is a lanky 6-foot-6, and he sat right around 90 mph during his three years at Northeastern. Even this April, he was sitting 94-95 mph in Double-A. On Thursday, Schlittler hit 100 mph 25 times and averaged — averaged — 98.9 mph with his fastball. His rise can best be described as meteoric.

“The interesting thing about him is he wasn’t always this kind of guy,” Ben Rice, who caught Schlittler in the minors, said in August. “I remember the year he got drafted, he started in extended spring training. He was not a velocity guy by any means. To his credit, he put in the work, put his head down, put on weight, put on muscle. He made himself into a really good pitcher.”

Not only was Schlittler electric Thursday, but he was a bad matchup for a Red Sox team that had issues with big velocity throughout the season. Particularly in September, after Roman Anthony hurt his oblique, they were among the worst teams in baseball against 95 mph fastballs and above. Boston’s weaknesses aligned with Schlittler’s strengths pretty much perfectly.

The Red Sox put the leadoff man on base in the second, fifth, and sixth innings against Schlittler but never had a runner reach third base. He struck out 12, the most ever by a Yankees’ rookie in the postseason, and the most by any rookie since Livan Hernandez struck out 15 in Game 5 of the 1997 NLCS (with an assist to Eric Gregg’s strike zone).

“I woke up and I was locked in,” Schlittler said. “I knew exactly what I needed to do and go out there, especially against my hometown team. As I told Andy (Pettitte) yesterday, I wasn’t going to let them beat me. I was just overconfident in that fact. Making sure I wasn’t getting too carried away with it.”

Schlittler is the first pitcher in postseason history, rookie or otherwise, to throw eight shutout innings while striking out 12 and walking zero. Game 3 was not an out-of-nowhere performance. Schlittler threw 73 innings across 15 starts with a 2.96 ERA during the regular season, and beat out reigning AL Rookie of the Year Luis Gil for Thursday’s start. He was out there because he earned it.

The Yankees lost Gerrit Cole to Tommy John surgery in spring training and managed to dig up a pretty good facsimile of Cole in Schlittler, who looks like a more-than-worthy No. 3 behind Max Fried and Carlos Ródon. He is a massive player development success story and and quickly cemented himself as an indispensable Yankee.

So now the Yankees are where they finished the regular season — tied with the Blue Jays. Schlittler’s gem put the Yankees in the ALDS against a Toronto team that beat them out for a division title via tiebreaker. Schlittler likely won’t start again until a possible Game 4 of that series, but without him, the Yankees might not even be playing in it.

“It is electric. Yankee fans are very passionate. It was very loud from the jump,” Schlittler said about the ovation he received coming off the mound after the eighth inning. “And that’s what they told me would happen. It was a great feeling and I was able to channel that energy. They were definitely behind me and the team. That was a great feeling.”