JUPITER -- It was estimated that nearly 18,000 men have played Major League Baseball, and only one, Adam Greenberg, had his career end on the first pitch.

More than seven years later, Greenberg is trying to get back that opportunity that was taken from him. And his efforts this week while playing for Israel in a World Baseball Classic qualifier could help him.

Matt Liston, a filmmaker from Santa Monica, Calif., knows about Greenberg because he is a Cubs fan, and his Chicago team was playing the Marlins in South Florida on July 9, 2005.

That’s when Greenberg’s life changed forever.

And now Liston wants to help him make it right.

With the ESPN Sunday Night Baseball cameras rolling, Greenberg made his big-league debut as a pinch-hitter in the ninth inning. Facing left-hander Valerio de los Santos, the left-handed Greenberg, now 31, said he was determined to be aggressive and not bail out of the batter’s box.

“He threw me a 92-mph fastball, and I turned to try to avoid it,” Greenberg said. “It caught me square on the back of my helmet, right on my actual skull.”

Greenberg was sent back to the minors, where he was on the disabled list for the next 21 days. But he experienced vertigo and intense headaches for the next 18 months.

“Anytime I would tie my shoes or roll over in bed or move too quickly, I would get these migraines that would go on for hours,” said Greenberg, a former Atlantic Coast Conference Rookie of the Year at North Carolina and a ninth-round pick of the Cubs. “More than baseball, I was concerned about my quality of life.”

Greenberg continued to play. He even got a hit off of de los Santos in a minor-league game last year.

“That was sweet — probably the biggest hit of my career,” Greenberg said of the single.

A speedy 5-9, 180-pound outfielder, Greenberg said he hit his low point in 2007, when he was released by the Kansas City Royals’ organization despite hitting .266 with 30 doubles, 11 triples, eight home runs and an on-base percentage of .373 at Double A.

The last time he was affiliated with a major-league organization was in 2008, with the Los Angeles Angels. He played independent ball until 2011, before taking this year off to start a business.

He’s married now, after all. He and his wife, Lindsay, were grade-school classmates in Guilford, Conn., but they hadn’t seen each other in nine years when they met again in 2008. They wed in 2010.

“We didn’t need to get to know each other,” Lindsay said, “because we already knew each other.”

In February, Greenberg was contacted by Liston, who had recently watched the film Field of Dreams with his wife, Marisa. When she said she felt bad for “Moonlight” Graham, the real-life player who played in just one major-league game (1905) in his career and never got a turn to bat, Liston thought of an ex-Cub.

“Moonlight’s got nothing on Adam Greenberg,” he told his wife. “Moonlight played two innings in the field. Adam didn’t even get two seconds.”

Liston proceeded to do his research and found that Greenberg was still playing.

With Greenberg’s permission, Liston created a website — www.oneatbat.com — and within a week had received 20,000 signatures for a petition to give Greenberg another shot in the majors.