An athlete or performer who fakes illness, injury or misfortune (e.g. missing equipment) in order to not have to appear in front of a rude crowd is said to have the Philly Flu.
It was particularly widespread among hockey players who were about to play the Flyers in the old Spectrum in Philadelphia, know for the rude Philly fans
MacTavish apparently has a case of the Philly Flu tonight. Apparently the primary symptom is that he left his skates at the hotel.