Major League Baseball said he had an elevated ratio of testosterone to epitestosterone, a violation of its drug rules.
The 34-year-old Ozuna was hitting .292 with 15 RBIs for Triple-A Lehigh Valley this season.
Ozuna played in the majors from 2000-08 with Florida, Colorado, the Chicago White Sox and Los Angeles Dodgers, batting .282 with three home runs and 45 RBIs. He played for the Dodgers in the NL championship series last year.
Phillies reliever J.C. Romero returned to the team earlier this month following his 50-game suspension for testing positive for a banned substance.