The Padres optioned Jacob to Triple-A El Paso on Sunday.
Jacob has been up with San Diego all season and had been pitching decently with a 3.34 ERA through 20 appearances, but he surrendered 10 earned runs over his past two outings, including four runs Saturday in Atlanta. The right-hander will head to the minors in favor of Omar Cruz, who will bolster the Padres' bullpen depth.