HOUSTON — Just when Giancarlo Stanton was changing his pinstriped narrative, he fell back into an old habit.

Not striking out too much. Getting injured too much.

In one sense, it actually served as progress for the $325 million man that his absence from the Yankees’ lineup for Sunday night’s American League Championship Series Game 2 — due to an ailing right quad — appeared to generate more concern than relief among the team’s fan base. That’s what happens when you actually perform well, as Stanton certainly did in Saturday’s Game 1, contributing a homer and single to his club’s 7-0 win over the Astros at Minute Maid Park.

But now the question changes, courtesy of the injury he suffered while running out his infield single in the second inning. It’s not a matter of whether he’ll hurt the team’s vibe with his anxious-looking at-bats, as certainly occurred in last year’s AL Division Series loss to the Red Sox. It’s how much the Yankees can even count on Stanton over this postseason and the next eight.

“I don’t think it’s a long-term concern,” Yankees general manager Brian Cashman said before the game of this specific injury. “Obviously, clearly, we’re dropping him into the deep end of the pool because of playoff baseball. … His return to play protocol has been truncated. It’s a worry of ours because of that. But again, this time of year, you have to do what you have to do to make sure you can put him in the lineup.”

Cashman was referring to Stanton’s hurried return, in the final two-ish weeks of the regular season, from a strained PCL in his right knee that kept him out of action for well over two months. And he missed another two-plus months in the first half due to a left biceps/left shoulder/left knee/left calf kinetic-chain thing.

He totaled only 18 regular-season games after playing in 158 last year, and an optimist will predict that Stanton, who turns 30 next month, should be good as new following a winter of rest, physical therapy and whatever other remedies enter the picture.

A pessimist, meanwhile, will look at the 6-foot-6, 245-pounder’s extensive injury history dating back to his Marlins days; proclaim, “The bigger they are, the harder they fall,” and wonder how many seasons of real value from the subsequent eight, during which time the Yankees owe Stanton $214 million, Cashman and his owners can realistically hope to get.

It sure looks like the Yankees must continue to be as resourceful as they proved to be this season, picking up the veteran Cameron Maybin for a song and receiving stellar production.

Maybin replaced Stanton in left field for Game 2, and Aaron Hicks, who himself dealt with two major injuries this season, became a more important reserve after working his way from the verge of Tommy John surgery on his right elbow to the active roster for this series.

Nevertheless, if Stanton showed anything in these first four games of the month, it’s how much of a force he can be when he’s even close to right. He compiled an impressive .300/.467/.600 slash line in 15 plate appearances, drawing four walks against the Twins in the AL Division Series. His sixth-inning laser off Astros stud Zack Greinke in ALCS Game 1 boosted the Yankees’ lead to 3-0.

“Obviously [we’re] disappointed because we feel like G’s really gaining some steam and having good at-bats, and we know what kind of impact player he could be,” Aaron Boone said Sunday. “But we know when we turn to Cam or Aaron in this situation, we know what they can be.”

They can be quite good. They can’t be peak Stanton, though. How much more of peak Stanton can the Yankees expect as they’re paying for just that?

You don’t want to contemplate this right now. You’re having too much fun this month. Fair enough. The Stanton cloud over the Yankees ain’t going anywhere. It’ll be waiting for you whenever you’re ready to talk about it.