24, 2010, the Pittsburgh Pirates traded Duke to the Arizona Diamondbacks for a player to be named later, determined to be César Valdez. On May 28, 2011, Duke was activated off the disabled list and made his first start with the Arizona Diamondbacks, replacing Micah Owings in the rotation. He also hit his first major league home run that day, a three-run home run off of Bud Norris. Duke made 9 starts in the rotation, going 2–4 with a 5.47 ERA, and opponents hitting .336/.368/.481 off of him. On July 15, Duke was relocated to the bullpen, where he fared slightly better in a long-relief role, recording a 3.86 ERA in 25.2 innings, only striking out 6 while walking 8. Overall in 2011, Duke was 3–4 with a 4.91 ERA in 21 appearances. On October 31, 2011, he elected to become a free agent. Houston Astros Duke signed a minor league contract with the Houston Astros on January 27, 2012. He also received an invitation to spring training; however, he was released on March 27. Washington Nationals Duke signed a minor league contract with the Washington Nationals on March 29, 2012 playing for the Washington Nationals's AAA affiliate, the Syracuse Chiefs. He was called up the majors on September 3 and appeared in 8 games, pitching 13.2 innings with a 1.32 ERA. On December 2, 2012, Duke resigned with the Nationals on a one-year deal to serve as the team's long reliever. He was designated for assignment on June 4, 2013, after posting an 8.71 ERA for the team in innings. On June 10, 2013, Duke was released by Washington. Cincinnati Reds Duke signed a minor league contract with the Cincinnati Reds on June 13, 2013. He eventually was promoted to the big league club and recorded an 0.84 ERA in innings. Milwaukee Brewers Duke was signed as a free agent on January 15, 2014, and invited to spring training by the Milwaukee Brewers for 2014 and made the roster as a left-handed relief specialist. He recorded his first win of 2014 on April 20 against the Pittsburgh Pirates. Duke had emerged as a key member of the Brewers' bullpen, finding success against lefties and righties. As of July 21, his ERA was a minuscule 1.16, and he had struck out 49 batters in innings pitched. He finished the year strong, recording a 2.45 ERA with 74 strikeouts to only