BOSTON — Why on Earth, given how well he’d pitched up until that point, would you take your stud, Cy Young hopeful pitcher out of a key game after just seven innings?

The answer to that second-guess, especially given how poorly it turned out for the Detroit Tigers is easy.

“He was spent,” Tigers manager Jim Leyland said.

When Leyland pulled Max Scherzer from Game 2 of the American League Championship Series after just 108 pitches, an inning after he’d given up no-hit and shutout bids in the span of three pitches, it turned the game over to a bullpen that gave up six combined runs in the eighth and ninth innings. The Red Sox tied it at 5-5 with an eighth-inning grand slam by David Ortiz, and won it on Jarrod Saltalamacchia’s walk-off RBI single.

Considering he’d struck out 13 and allowed just two hits before he left, it’s safe to assume that Scherzer could’ve done better than that.

Except he had nothing left to give.

And he had no problem with when he came out, had no second-guessing of his manager.

“No. I told them I was done. They wanted me done. They had it all lined up how they wanted to approach the eighth inning,” Scherzer said. “I just knew I was at my limit. You gotta be smart. It’s still early in the series. You gotta gauge your health, because my health is important to the team, and I’d reached my pitch-count limit, where I was tonight.”

That didn’t necessarily show — in terms of results — in the way he finished out his stint, after giving up the no-hitter and shutout in the sixth, on a single by Shane Victorino and a double by Dustin Pedroia. Scherzer struck out Ortiz swinging to end the sixth, then struck out the first two batters of the seventh, and finally got Saltalamacchia to ground out to finish it.

Considering he made 15 starts — regular season and postseason combined — in which he threw more than 108 pitches, that alone doesn’t mean he was ready to come out. Leyland says his decision is usually based on multiple decisions, in addition to pitches thrown, including how the pitcher is throwing at the time, and if he seems to be laboring.

And the manager trusts his pitchers — for the vast majority of the time — to tell him the truth about how they’re feeling.

In the seventh, Scherzer was feeling it.

That’s why he can’t necessarily fathom why fans might question the decision so readily.

“No. I was done. You can write that. I was done. Everybody, they wanted me done, I was done. I was not going out there for the eighth inning,” he said. “I knew I was at my pitches, I knew I was reaching the end. I could tell on my arm. My arm was getting tired. I was getting to the end of my line.

“This is nonsense.”