An MRI on Casparius' right calf came back negative Wednesday, Sonja Chen of MLB.com reports.
Casparius first felt his calf cramping while warming up prior to an appearance in Tuesday's 10-7 loss to the Twins and he was pulled after letting four straight batters reach base. While he doesn't have any structural damage and is expected to avoid the 15-day injured list, Casparius is likely to be unavailable to pitch for a few days.