(CNN) -- Adam Greenberg signed a one-day contract with the Miami Marlins on Tuesday afternoon in anticipation of taking a single at-bat in the night's game against the New York Mets.
Greenberg, now 31, was hit in the head by a pitch in his first and only Major League Baseball plate appearance, with the Chicago Cubs in 2005 and has not played in the majors since. A hit-by-pitch does not count as an official at-bat, so Greenberg technically has never batted in the major leagues.
He petitioned the Cubs to let him come back for one official at-bat with them, but team officials turned him down. The Marlins agreed last week to help Greenberg make his dream come true. Marlins manager Ozzie Guillen said he plans to use him as a pinch-hitter in the middle of Tuesday night's game, perhaps in the pitcher's spot in the lineup, according to MLB.com.
"I'm ready to help the team," Greenberg said in a tweet on the Marlins' account. "The Marlins are an amazing organization. ... I couldn't be more thankful."
The pitch that knocked him out may have derailed a longer MLB career.
On July 9, 2005, Greenberg stepped up to the plate to pinch-hit for the Cubs, who had just called him up from the minors, at Miami's Dolphins Stadium.Valerio de los Santos' pitch hit Greenberg in the head and sent him to the ground. Greenberg, in severe pain, had to leave the game without playing defense and no official at-bat -- it counts only as a plate appearance.
As Chicago Magazine and ESPN's "Outside the Lines" have documented, Greenberg was dizzy for months, had blurred vision, and had trouble playing when he returned to the minors weeks after the incident. He eventually was diagnosed with positional vertigo.
Symptoms eventually improved, but he struggled in the minors. He last played professionally in 2011 for the Atlantic League's Bridgeport Bluefish in his home state, Connecticut, where he runs his LuRong Living business.
ESPN kept Greenberg's story alive with a couple "OTL" segments. And this year, filmmaker Matt Liston made it his mission to get him a real MLB at-bat.
Liston, a Cubs fan and Chicago native living in California, took up Greenberg's cause this year after he and his wife saw "Field of Dreams" -- a baseball movie that mentions Moonlight Graham, who never came to bat in his only big-league game in 1905.
"My wife said she felt sorry for him. I said, 'Moonlight Graham has (nothing) on Adam Greenberg,'" Liston said. "Graham played a couple innings. Adam only got a couple seconds."
Liston, who didn't know Greenberg but recalled seeing the plate appearance on TV, decided he wanted to help him get a proper MLB at-bat. So, armed with credentials -- he made the 2007 film "Chasing October" about the 2003 Cubs -- he visited baseball training camps, trying to persuade players and general managers that Greenberg deserved a shot.
He and a dozen or so friends organized the "One At Bat" campaign, taking to Twitter and Facebook to rally public support. They also started a Change.org petition -- it had more than 25,000 supporters as of Thursday -- that Liston hoped would persuade the Cubs' management to bring him back for a game this month. Liston, who met with the Cubs in May, also contacted Greenberg and ended up befriending him as he kept him updated.
But the Cubs announced this month that they weren't on board.
"Adam made the big leagues based on merit in 2005," Cubs General Manager Jed Hoyer told the Chicago Tribune in an e-mail. "While it is unfortunate he got hit in his first at-bat, he is in the Baseball Encyclopedia as a major leaguer and should be incredibly proud of that. We wish him the best, but there are no plans to add him to the roster now or in the future."
So Liston pressed other teams, eventually meeting in New York with the Miami Marlins General Manager David Sampson. There, Sampson told Liston that the Marlins would do it.