Jeffrey Joseph Marquez
- Bats Right Throws Right
- Height 6'2", Weight 175 lbs
- School Sacramento City College
- High School Will C. Wood High School
- Debut July 9, 2010
- Final Game June 19, 2011
- Born August 10, 1984 in Vacaville, CA USA
Jeffrey Marquez was the New York Yankees' supplemental first round selection in the 2004 amateur draft, with the 41st pick. He was signed by scout Jeff Patterson and assigned to the GCL Yankees. After four games (2 starts) Marquez put together a 2-0 record with a 0.63 ERA and was promoted to the Staten Island Yankees. In Staten Island, Marquez went 2-4 with a 3.02 ERA. He spent all of the 2005 with the Charleston River Dogs where he struggled with a 9-13 record but only a 3.42 ERA. In 2006 Marquez was back in the Gulf Coast League for 2 games, taking a loss, before going up to the Tampa Yankees. With Tampa Marquez put up a 7-5 mark with a 3.61 ERA and 82 strikeouts. Baseball America ranked him as the 9th best prospect in the Yankees system in 2006. He started the 2007 season with the Trenton Thunder.
On November 13, 2009, he was traded to the Chicago White Sox along with Wilson Betemit in return for Nick Swisher. He made his major league debut with the White Sox on July 9, 2010, giving up two runs in one inning of relief against the Kansas City Royals. He was sent back to the minors after that game.