Jacob is out with a right shoulder injury, Sam Dykstra of MLB.com reports.
A 24-year-old righty reliever, Jacob had a 2.68 ERA, 1.12 WHIP and 77 strikeouts in 57 innings across stops in the three highest levels of the minors last year. If he is able to get healthy, he would probably be assigned to Double-A or Triple-A.