The Nationals have announced that they signed Zach Duke to a minor league deal. The Astros released the left-hander earlier this week after signing him to a minor league deal in January.

Duke, 28, posted a 4.93 ERA in 21 appearances, 9 of them starts, for the Diamondbacks in 2011. He also posted a 49.6% ground ball rate for Arizona. Before last year, Duke had averaged around 31 starts a year for the last three seasons.

Duke was a promising young pitcher as a 22-year-old in 2005, when he posted a 1.81 ERA in 84.2 innings pitched, good for a 235 ERA+. Duke hasn't lived up to his hype, struggling in five seasons with the pirates. 2009 was Duke's best season, when he went 11-16 with a 4.06 ERA in 213 innings pitched and was named to the All-Star team. Unfortunately he fell to a 5.72 ERA in 2010, as he gave up a career high 25 homers.