As a person in HR, I’ve dealt with this all year. A person can test negative and then posit e an hour later as the virus is incubating. That’s why they mandate a 14 day quarantine for known contacts EVEN IF that contact gets a negative test right away (rules for ordinary citizens via Departments of Health). He could have contracted this as many as 14 days prior to Sunday and in just then developed in him to kick the positive test. This could have happened without any mishandling on their part. It does, however, mean he exposed himself somewhere to the virus. In theory it could have been a player from the previous Ravens game or, like most cases, through regular human interaction since no team is in a “bubble” like the NHL had this summer.