Michael Jordan is coming clean about his epic flu game performance in the 1997 NBA Finals ... saying he didn't actually have the flu -- it was some bad pizza.
Remember, #23 was dealing with "flu-like symptoms" before a crucial Game 5 against the Utah Jazz ... and fought through the pain for a 38-point performance to give the Bulls a 3-2 lead.
But, MJ's trainer, Tim Grover, revealed it was actually food poisoning -- not the flu -- that had Jordan under the weather ... after a late-night order from the only place that was open -- a pizza shop.