Pruitt's contract was selected by the Athletics on Saturday.
Pruitt joined the Athletics on a minor-league deal in March, and he posted a 3.27 ERA and 0.95 WHIP in 22 innings over 12 relief appearances at Triple-A Las Vegas to begin the year. The right-hander made just six major-league appearances between the Marlins and Astros last year, and he should serve mainly as a low-leverage reliever in Oakland.