Strop is battling a sore left calf and will not throw off the mound Thursday, Mark Gonzales of The Chicago Tribune reports.
Strop's injury isn't considered to be anything serious but the Cubs aren't going to take any chances with the right-hander. He may be kept off the mound for a couple days in order to ensure no further setback but he will toss off flat ground prior to Thursday's Cactus League game against Colorado.