It doesn’t sound like a serious concern. However, at this early junction in camp, the Twins weren’t going to take any risks with their staff ace, even if he experienced even minor discomfort while warming up — especially after losing Pablo López to Tommy John surgery earlier this week. Even minor back discomfort can linger if not managed properly, so this decision appears to be precautionary in nature. It’s unclear whether he’ll undergo further evaluation and testing to determine the severity of the issue. There should be additional updates on his status in the coming days.