(CNN)Just over a month after Buffalo Bills safety Damar Hamlin went into cardiac arrest after making a tackle in a game against the Cincinnati Bengals, the Buffalo Bills safety has received an optimistic prognosis on his playing future from the NFL players union doctor.
"I guarantee you that Damar Hamlin will play professional football again," Dr. Thom Mayer, medical director of the NFL Players Association, said on SiriusXM Doctor Radio's "Heart to Heart" program on Wednesday.
Hamlin collapsed after making a tackle in the first quarter of the game against the Bengals on January 2.
Doctors and trainers administered CPR and used a defibrillator on the field to resuscitate Hamlin before he was taken out of the stadium in an ambulance, leaving players, coaches, fans and the TV audience in shock.
Medical officials said he went into cardiac arrest, meaning his heart abruptly stopped beating. The game was postponed and ultimately canceled.
Hamlin was admitted to the University of Cincinnati Medical Center before being transferred to a Buffalo medical center on January 9 and released on January 11. The cause of his collapse still has not been determined.
Subsequently Hamlin has made remarkable progress, and he was discharged from a Buffalo medical center on January 11.