NEW YORK — The NYPD officer stood on a metal bench inside the Houston Astros’ bullpen and pointed at a fan in the Yankee Stadium left field bleachers.

“Get him out!” the officer said.

Immediately, another cop grabbed the man, escorted him up the bleacher steps and out of the stadium.

Fans at Yankee Stadium were taunting Astros starting pitcher Zack Greinke during his warmup before he faced the New York Yankees in Game 4 of the American League Championship Series on Thursday night.

The ugly scene came after the Astros — including manager A.J. Hinch and right fielder Josh Reddick — complained about fans throwing trash at players and onto the field during the Yankees’ Game 3 defeat.

NJ Advance Media spent from 7:40 p.m. until about 8 p.m. in the bleachers, watching the chaos.

Chants digging at Greinke’s battles with a social anxiety disorder and depression rained down on the 35-year-old right-hander as he threw to a catcher.

Fans leaned over the concrete barrier between the stands and the bullpen and shouted insults about Greinke’s mother, too.

They also chanted “Donald,” Greinke’s first name.

Two police officers were stationed inside Houston’s bullpen, their backs against the wall as they looked toward the bleachers.

Another three uniformed officers were dispersed throughout the bleachers.

One of the officers stationed inside the bullpen pointed to a fellow cop in the bleachers and mouthed to him: “First one to mouth off, get him out.”

One officer pulled a fan aside and told him he would have to eject any fans that cursed at Greinke.

And at one point, Astros bullpen catcher Javier Bracamonte stood and watched a fan who hurled insults at him. Bracamonte then walked toward the cops in the dugout and smiled while watching the fan.

The Astros were obviously concerned for the safety of their players.

So was stadium staff.

About 45 minutes before first pitch, the main center field scoreboard displayed a message that warned fans that they would be arrested for throwing things onto the field.

And after the second inning, Yankees manager Aaron Boone appeared on the video board, stressing the importance of safety for fans and players.

“The Yankees continue to stress the highest importance on player and fan safety — now and forever,” a team spokesman said.

The NYPD didn’t immediately respond to a message seeking comment.

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In the afternoon, Astros manager A.J. Hinch threatened to “pull the team off field” if Yankees fans continued to throw trash onto the field near his outfielders, the way they had in Game 3 on Tuesday night.

“I will pull the team off the field if we get in that situation again where bottles are being thrown and balls are being thrown and it becomes unruly,” Hinch said. “There's other ways to support your home team, and this place does as good a job as anybody to trying to police that while also trying to create an environment that's all pro-Yankees. It would be a very ugly scene for baseball, a very ugly seen for the Yankees, if one of our guys was hit by something from the upper deck. Something tragic could happen and nobody wants that.”

On Tuesday, Reddick called Yankees fans “disrespectful.”

“I think I saw about seven or eight water bottles out in the outfield, two baseballs got thrown from center to left,” Reddick said. “It’s scary. I don’t think a lot of people realize how dangerous that can really be. You throw a baseball hard enough and it hits somebody in the head when you’re not looking, it can do some damage to you as a player. It’s definitely disrespectful and at the same time, unsafe.”

Brendan Kuty may be reached at bkuty@njadvancemedia.com. Follow him on Twitter @BrendanKutyNJ. Find NJ.com Yankees on Facebook.