I will assume from your definitive statement dismissing the diagnosis of flu that you hold an MD and completed a fellowship in Infectious Disease. If so, could you please enlighten the board on what you are basing this conclusion.
By my understanding (as a physician but not, admittedly, an ID expert), it is quite possible for someone to be past the contagious period (typically 3-4 days) and therefore be allowed to sit next to the team, but not be recovered enough to resume full physical activities and therefore not cleared by team doctors for full participation.
Until I hear someone quote a reputable source that states that the flu was a cover story, I will choose to believe the official NU report that Page was unavailable due to illness.