Ennis pitched 4 innings in his first MLB game; however, that one appearance was his only appearance for the Braves. He pitched 16 innings in 12 appearances for the Detroit Tigers in 2004, posting an 8.44 ERA. Ennis made his Philadelphia Phillies debut on August 26, 2007, pitching three innings and getting his first career save. He was designated for assignment by the Phillies on February 26, 2008. On August 6, 2008, Ennis' contract was sold to the Samsung Lions of the Korea Baseball Organization (KBO), where he pitched for the rest of the season.
After pitching in the first game of the season, Ennis suffered an injury to his elbow and was told he needed Tommy John surgery which would end his season. The Phillies released him on November 10, 2009.