Masahiro Tanaka has been mostly brilliant in the postseason since joining the Yankees.

They will need the right-hander to live up to his lofty standards again in Game 4 on Thursday in The Bronx if they are to have a realistic chance of coming back in this ALCS against the Astros.

Not only do the Yankees trail, 2-1, but with Wednesday’s game pushed to Thursday due to rain, Aaron Boone likely will be forced to test his bullpen more than he has all season if the series extends to seven games.

“We’re going to have to get some innings out of our starters, there’s no question about it,’’ Boone said Wednesday during a conference call. “Obviously Masa is coming off a real good start in Game 1 where he was able to give us six innings. So between him and [James] Paxton these next two days, they’re going to need to give us some innings if we’re going to be successful.’’

History says Tanaka will deliver. In seven postseason starts, Tanaka has never allowed more than two runs or pitched fewer than five innings. And he’s been even more dominant in his past four playoff outings, dating back to Game 5 of the 2017 ALCS against the Astros. Over that stretch, Tanaka is 4-0 and has given up just two runs in 23 innings, good for an ERA of 0.78. He’s struck out 23 and walked only four.

Tanaka rarely has been better than he was in Game 1, when he held Houston to one hit and one walk and faced the minimum 18 hitters in six scoreless innings.

“Any time the moment gets really big, he is good at slowing the game down himself and maybe taking even a little bit off of his pitches as opposed to powering through it,’’ Houston manager A.J. Hinch said Wednesday. “We’d like to see us have a more disciplined approach, but that’s easier said than done with the stuff he has.’’

Tanaka said he worked even more deliberately than usual in the Game 1 because of Houston’s reputation of picking up on tipping pitches. The Yankees altered signs during at-bats, even when no one was on base.

“We tried to make it more complicated,’’ the right-hander said afterward through an interpreter. “We definitely paid more attention to changing things up and tried to make it harder for them.”

Boone also pointed to Tanaka’s “ability to not make any kind of a moment or start bigger or less than it is.’’

Tanaka will bring that mentality into Thursday’s game, knowing what’s at stake. Not only do the Yankees need a victory, they would like to avoid taxing the bullpen.

Boone said he would use a pitcher three consecutive days if he needed to — something the Yankees didn’t do with their relievers all season — but still would be careful in their deployment. With Paxton slated to start Game 5 and a potential bullpen game looming in Game 6, the pen will be counted on plenty.

It’s up to Tanaka to put that off for one more day.