Parra attended spring training with the Brewers in 2007 where he allowed no runs or hits while striking out 3 batters in  innings over 4 relief appearances. He was assigned to Double-A Huntsville to begin the 2007 season. After 13 starts, he had a win–loss record of 7–3 with a Southern League-leading 2.68 ERA. He was promoted to the Triple-A Nashville Sounds in mid-June to replace ace pitcher Yovani Gallardo who had been called up to Milwaukee. Parra made his first career Triple-A start on June 20—a 3–0 loss in which he allowed 2 runs on 7 hits and 4 walks while striking out 6 batters in 6 innings.