SAN DIEGO -- Making its postseason debut this fall, the three-batter minimum is already wreaking havoc on the best-laid plans of big league managers.

Take Kevin Cash Sunday night, for instance. The Rays’ skipper didn’t have many options for the eighth inning of his team’s 2-1 victory over the Astros in Game 1 of the American League Championship Series. Both Peter Fairbanks and Nick Anderson were unavailable after their heroics against the Yankees on Friday.

So Cash called on left-hander Aaron Loup, a palatable solution with the lefty-hitting Michael Brantley due up first.

No, Loup hadn’t pitched since Sept. 30. Yes, two of the sport’s hottest right-handed hitters loomed after Brantley in Carlos Correa and Alex Bregman. That was fine with Cash -- because he liked Loup’s first matchup.

• Castillo saves Game 1 -- and maybe Game 2

“When we don't have Nick and Pete, figured Loupy was fresh,” Cash said. “[He] just comes out and, first pitch, didn't have his bearings straight. Ideally, you don't hit the first left-hander you see.”

Indeed, Loup’s first pitch was a 93-mph fastball that connected with Brantley’s backside. Cash’s reaction spoke volumes.

In a different postseason, it would’ve been fair to expect Cash to hop from the top step of his dugout, stroll toward the mound and summon a right-hander. This was, after all, the game’s highest-leverage spot, and the Rays were at a disadvantage with a lefty like Loup on the hill.

That wasn’t an option for Cash, because of this year’s rule change mandating that a reliever face at least three hitters or finish an inning. So Cash plopped his forehead on the railing of the dugout for a moment, before turning and barking at no one in particular.

Without the rule, Cash might’ve called for righty Aaron Slegers. He might’ve gone early to Diego Castillo. He couldn’t.

“Sometimes you're going to get penned in there -- penned into those situations that make you a little uncomfortable when you know you've got a guy down there that you'd probably rather have,” Cash said.

The scene was somewhat reminiscent of Game 2 of the AL Division Series against the Yankees. With a three-run lead in the ninth, Fairbanks walked the first two hitters he faced.

Again, in a different postseason, Cash’s decision making probably would’ve unfolded differently. The Yankees had the tying run at the plate, and Fairbanks was laboring. But if Cash wanted a different arm, he didn’t have that choice.

So he stuck with Fairbanks, who promptly struck out Clint Frazier and Gary Sanchez. DJ LeMahieu singled home a run, but Fairbanks put a lid on a crucial Game 2 victory by getting Aaron Judge to ground out.

Sure, the rule was implemented at the beginning of the regular season. But late-game pitching strategy is hugely magnified in the playoffs, and its impact is only now on full display.

“I wasn't thrilled with it,” Cash said when asked for his initial opinion on the rule. “I don't know if I've changed my mind or not. Ideally, you recognize it, you get used to it. We had a little bit of spring, and you get 60 games to prepare for it.”

Learn the rule and adjust to it. In the eyes of Rays catcher Mike Zunino, that’s what makes Cash so good at what he does.

“There's not many bad decisions out there,” Zunino said of the Rays’ bullpen. “But it can't go overlooked the timing of when Cashy makes his moves. He's on top of it. That goes without saying. That's the reason why I think he's the best manager in the game.”

Then again, sometimes Cash has those decisions taken out of his hands. Sometimes he simply has to stick with Loup against two ferocious right-handed hitters, because he’s mandated to do so.

And sometimes it works out.

Loup atoned for plunking Brantley by blowing a 95-mph fastball past Bregman for strike three. He walked Correa, and Cash stuck with Loup for one more batter, the lefty-hitting Kyle Tucker -- who singled to left, loading the bases.

The decision back in his hands, Cash called for Castillo to face the switch-hitting Yuli Gurriel.

“With the traffic and everything, just decided to get Diego in the game,” Cash would say.

Sure enough, Castillo worked his way out of the jam by inducing a double play with his first pitch. Cash, at long last, could exhale.