The Padres optioned Jacob to Triple-A El Paso on Saturday.
After returning to the majors at the end of August, Jacob allowed three earned runs over 8.1 innings across three appearances, though he hadn't pitched in a game since Sept. 14. He'll now head back to the minors as the Padres sacrifice some of their bullpen depth to bring back Randy Vasquez, who will start Saturday's game against the Diamondbacks.