Howard is rehabbing an undisclosed injury at extended spring training, MLB.com's William Boor reports.
A third-round pick in 2014, Howard split time between High-A and Double-A last year, posting a 3.35 ERA, 1.33 WHIP and 140 strikeouts in 156 innings. He profiles as either a middle reliever or back-end starter, depending on the development of his changeup.