The mystery has been uncovered.
WFAN reported Tuesday morning that Matt Harvey was suffering from from blood clots in his bladder, and had a procedure on Monday that was the reason for his Mets absence.
Harvey is reportedly feeling much better and was back at Mets camp on Tuesday, though was immediately ushered in to consult with trainer Ray Ramirez.
It is unclear whether Harvey’s recovery means he will miss his scheduled Opening Day start on Sunday night against the Royals.