A Long Island Little League coach died after he was struck in the head with a baseball during warm-ups before a game Saturday night, authorities said.

Richard Becher, 50, was on the mound during batting practice at a facility called at Baseball Heaven in Yaphank, Suffolk County, when a 12-year-old batter smacked a ball right up the middle that plunked him in the head and knocked him unconscious, according to officials.

“He was an amazing person, an amazing father, son, friend,” family friend Denise Volpicello told The Post.

“It’s devastating for everyone. He was very active in the community. It’s a tremendous loss.”

The young player hit the ball that struck Becher sometime around 5:30 p.m., authorities said.

Becher’s brother-in-law said the devoted baseball dad — whose son played on the team he coached — was struck hard by a line drive.

“He threw a pitch, the ball got hit. It was a line drive,” John Bree, 51, told Newsday. “He was hit in the head. He dropped to the ground.”

Several bystanders attempted to revive the unconscious Becher with CPR while waiting for police and EMS to arrive.

Becher, who lived in nearby Holbrook, was rushed to Brookhaven Memorial Hospital Medical Center in East Patchogue, where he was declared dead, police said.

“It was obviously a tragic situation,” said Roger Pondel, a spokesman for Baseball Heaven. “Our hearts go out to the family.”

Becher, a married father of two, was reportedly pitching from behind an L-screen, which is designed to protect players from this sort of injury, when he was struck.

Michael Rubenstein, the president of Sachem Little League, said it was a freak accident.

“It’s pretty rare [to get hit] if you’re behind the screen, but you can stick your head out for a second” and expose yourself, Rubenstein told Newsday.

The team was preparing for a Tri-State Tournament game Saturday night. The game was canceled after the tragic incident.

Becher was a board member of Sachem and the Ronkonkoma Youth Organization.

His friends on Long Island were heartbroken by his death and mourned him on social media.

“The Sachem community lost a great man last night,” Christopher Pierre wrote on Facebook. “Rich was always the life of the party, had the ability to make you laugh.”

Pierre added that Becher was a constant presence on the field and was respected throughout the community.

“His tragic passing was where Rich was usually found, on a baseball field with his son and his team,” he said. “His untimely passing is a constant reminder how in a split second, life is altered. It’s hard for me to believe this isn’t a nightmare.”

Another friend remembered Becher for his enthusiasm for the game.

“Always full of energy when he came into the academy,” Tom Downey wrote on Facebook. “Always reminded the kids that they were suppose to have fun. I’ll always remember that about him.”

Becher was the owner of Bech Air Corp., a sheet-metal-installation company on Long Island.