The Nationals designated lefty Zach Duke for assignment, according to a team press release. In a series of moves, the Nats also designated reliever Henry Rodriguez, reinstated Jayson Werth from the DL, placed Danny Espinosa on the DL, recalled Anthony Rendon, and selected the contract of Ian Krol.
Duke, 30, posted an 8.71 ERA, 4.8 K/9, 3.5 BB/9, 0.87 HR/9, and 54.4% groundball rate in 20 2/3 innings this year. He faced more right-handed hitters than left, but those in those 30 plate appearances from lefties they hit .448/.467/.552 against him. The Nats had re-signed Duke to a Major League deal worth $700K in December.
Duke was drafted in the 20th round by the Pirates in '01, and finished fifth in the NL Rookie of the Year voting when he came up and posted a 1.81 ERA in 14 starts in '05. He also snagged an All-Star nod in '09.
Krol was acquired from the A's in March to complete the three-way trade that sent Mike Morse to Seattle, John Jaso to Oakland, and A.J. Cole to the Nats. The 22-year-old lefty was dominant in Double-A this year, with a 0.69 ERA, 10.0 K/9, 2.4 BB/9, and one home run allowed in 26 innings.