Petit was released by the Padres on Thursday, Jeff Sanders of The San Diego Union-Tribune reports.
Petit signed a minor-league contract with the Padres in early May, but he posted a 7.71 ERA and 1.96 WHIP in 11.2 innings over 11 relief appearances at Triple-A El Paso. The right-hander saw plenty of work in the majors in recent seasons but will return to free agency after failing to generate much production in the minors over the last month.