Logan says he has brain damage from all the sparring he's doing in preparation to battle KSI in the ring again ... and we don't doubt him. He doesn't seem to be "all there," though he never really has ...

Logan Paul is jacked UP and ready to fight -- so much so that fans and frenemies are calling for him to take a drug test before the Nov. 10 rematch, which haters suspect he'll fail. Even Paul himself captioned an Instagram post recently, "I hope I pass my drug test."

Regardless of the 'roids, who do YOU think will win? Vote in our Face Off poll!