People.com said Miller lost his footing, fell and hit his head on the pavement after finishing a podcast with comedian Adam Carolla last spring. He slipped into a coma and was put on life support at UCLA Medical Center for a month.
"He was hovering between life and death," his representative Michael Hansen told People.com.
"It's a miracle he woke up. ... He's lucky to be alive," Hansen said. "He had to work on some issues regarding brain connectivity."
"I'm very thankful to have recovered from a traumatic brain injury so quickly," Miller told People.com.