He played eight seasons in Major League Baseball (MLB) between 2004 and 2013 for the Atlanta Braves, Tampa Bay Devil Rays, New York Yankees, Seattle Mariners, Boston Red Sox, Los Angeles Dodgers, Toronto Blue Jays, and Miami Marlins.

On July 2, 2004, Green hit a walk-off home run in the bottom of the 12th inning to lead the Braves to victory over the Boston Red Sox.

Prior to the 2005 season, the Tampa Bay Devil Rays received Green in a trade with the Braves in return for right-handed pitcher Jorge Sosa.

After starting the season with the Pittsburgh Pirates organization in 2007, Green was traded to the Seattle Mariners on June 20, 2007, and assigned to their Triple-A affiliate, the Tacoma Rainiers.

After teammates Julio Lugo and Jed Lowrie were both placed on the disabled list early in the season, Green became the Red Sox's starting shortstop.

On June 21, 2009, Green hit a first pitch walk-off home run to lead the Boston Red Sox to a 6-5 victory over the Braves.

With the Red Sox not scoring enough runs to warrant a new pitcher, Francona made the decision to have Green pitch in the ninth inning as well.

Green was also the first Red Sox position player to pitch multiple innings in a game since David McCarty did it in 2004.

[5] On April 4, 2010, he was the last man cut from the Major League roster out of spring training, and accepted his assignment to the Albuquerque Isotopes, the Dodgers' Triple-A franchise.

On December 10, 2010, Green was widely reported to have signed a minor league deal with an invitation to spring training with the Baltimore Orioles.

On July 19, 2011, Green, along with cash, was traded to the Texas Rangers for minor league pitcher Zachary Phillips.

He spent the bulk of the season with the Triple-A New Orleans Zephyrs before getting called up on August 4, 2012, when Emilio Bonifacio was placed on the DL with a sprained left thumb.