Kremer felt something in his oblique while warming up in the bullpen during Sunday's loss to the Rays, Nathan Ruiz of The Baltimore Sun reports.
Kremer was in the mix to operate as Baltimore's No. 5 starter to begin the season, but he was instead warming up to come out of the bullpen Sunday before the oblique issue cropped up. The specifics of the injury remain unclear, and the 26-year-old should be considered day-to-day until the team updates his status.