I thought it meant a distinction from the odd definition of close contact. The "close" part seems to indicate the consecutive length of time they are in contact, not the actual distance. The Bills linemen would have had contact with him over the course of hours, but obviously not for 15 consecutive minutes, hence no "close contact" and instead "continual contact for hours". Being 1 foot away from him for a minute isn't considered close contact, but being 5 feet away for 15 minutes is.