"Steve had an accident exiting his van yesterday to speak at the Gleason Life Skills Volleyball Clinic," the ALS advocate's wife, Michel, said on Sunday. "It was traumatic for him and for all of us who witnessed him mangled on the asphalt."

"Miraculously, he was spared greater injury because he was strapped into his wheelchair and because of the swift action of his care team, a passerby doctor, and family."

The family shared photos from the aftermath that show a visible bruise on his forehead -- but the 47-year-old seems to be in good spirits otherwise ... and he is now at home recovering.

The family was even able to add some humor to the post -- making a joke about how the van was preparing Steve for his fight against Jake Paul -- a post that went viral shortly after Paul defeated Mike Tyson.

Gleason -- who famously blocked a punt in the Saints' first home game at the Superdome following Hurricane Katrina -- was first diagnosed with Amyotrophic Lateral Sclerosis back in January 2011 at the age of 34 ... and has since used his platform to raise awareness of terminal disease.

He was hospitalized back in September during Hurricane Francine -- suffering from low blood pressure and a fever.