MJF suffered a hyperextended knee on the June 3 episode of AEW Dynamite during his AEW World Championship defense against RUSH, per Fightful Select. The injury occurred on a RUSH knee strike in the corner — not the tombstone on the barricade, which had been widely speculated online. There is no heat on RUSH, as it is described as a freak accident.
MJF withdrew from a booking at Beyond Wrestling this weekend as a result. He is expected to continue appearing on AEW programming while the company monitors the injury.