The Phillies optioned Kennedy to Triple-A Lehigh Valley on Tuesday, Corey Seidman of NBC Sports Philadelphia reports.
The 25-year-old was called up by Philadelphia on Sept. 6 but will return to Triple-A with Edmundo Sosa (back) being activated from the injured list Tuesday. Kennedy appeared in seven games during his brief time in the majors and went 2-for-10 with a double, two walks, two RBI and a run scored.