The 6-foot-3, 215-pound right-hander was selected by the New York Mets in the third round of the 2004 First-Year Player Draft out of a Miami-area high school. He made an immediate impression by leading the Gulf Coast League with a 1.09 ERA, striking out 58 batters over his first 49 2/3 pro innings.
He was equally impressive in his first full season, reaching Class A Advanced as a teenager. In the first half of 2005, Hernandez was a South Atlantic League All-Star, posting a 2.43 ERA and .179 opponents' batting average before struggling a bit following a promotion to the Florida State League. That offseason, he was sent, along with outfielder Dante Brinkley, to the Marlins for catcher Paul LoDuca. In his first full season with the Marlins organization (2006), Hernandez was outstanding, spending the season in the FSL at age 20 and going 9-7 with a 3.68 ERA and a nifty 115/35 K/BB ratio in 120 innings. His 2007 season was a little up and down, though he was a Southern League All-Star at age 21 and topped the 150-inning plateau for the first time.
During Spring Training this year, Hernandez was briefly in the mix to be the Marlins' No. 5 starter. He pitched well in camp but eventually got sent down and began the year with Triple-A Albuquerque. Things didn't go well for him in New Mexico, as he went 2-8 with a 7.24 ERA over 13 starts, spending nearly a month on the disabled list with an intercostal strain before being sent down to Double-A to get straightened out. He has gone 3-0 with a 4.30 ERA in four starts since and has looked much sharper.
When Hernandez is right, he's got a good three-pitch mix: a fastball that sits in the low 90s and can reach 94 mph; a breaking ball that is a plus at times; and a changeup that is also above average. Even with his demotion to Double-A, Hernandez is still fairly young for his level and could be ready for a big league callup in 2009.
Jonathan Mayo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.