Mock began the 2006 season pitching for the Tennessee Smokies of the Double-A Southern League, where he accrued a 4–8 win–loss record and 4.95 earned run average (ERA) in 23 starts.

After joining the Nationals organization, he pitched for the Harrisburg Senators of the Double-A Eastern League, compiling a 10.26 ERA in his first 4 starts, all losses.

His 2006 season ended September 2, after undergoing surgery to repair a tear in the patella tendon of his knee.

[3] In 2008, after starting the year with the Triple-A Columbus Clippers, Mock made his major league debut on June 8, giving up four earned runs in 4+1⁄3 innings.

On November 7, 2012, Mock signed a minor-league deal with the Arizona Diamondbacks with an invitation to spring training.