He is living with Parkinson's disease but no longer shuffles his feet moving from room to room or needs help getting dressed. His face, previously frozen in place as the medicine he took lost its effectiveness, now bears a smile.
He looks — and feels — more like the rugged forward he was during his 11-year NHL career.
"It's just great to be free again," Peterson said.
Freedom is all Peterson had ever known as the 12th overall pick by Detroit in 1978. He played 620 games with the Red Wings, Buffalo, Vancouver and Hartford as a top defensive forward, before moving into coaching.
But he was diagnosed with Parkinson's in 2003, and the progressive disease forced him off the bench after the team's playoff run last spring when it became unsafe for him to be on the ice. With medication less effective and side effects tougher to endure, Peterson turned to a procedure called deep brain stimulation in which surgeons implanted probes directly into his brain.
"It saved my life," Peterson said recently. "It's been unbelievable. The doctors are so good and unbelievable. ... And I hope I can help out. The reason we wanted to make everybody aware of it, if we can help one person in the next year, it's great. That's worthwhile."
The change has been dramatic.
The Predators, who open their Western Conference semifinal series against Phoenix on Friday, even sent the 54-year-old Peterson on scouting assignments during the first-round of the playoffs. Coach Barry Trotz said it was hard watching Peterson go through days when his body was so locked up that he struggled to button his shirt, even using Velcro. Trotz couldn't be happier for his friend.
"It's not necessarily because he can move around," Trotz said. "It's like someone getting a near death experience and having a chance to live again. He's getting that second chance. Not too many people get to do that."
Peterson was diagnosed when his wife, Tami, prodded him to visit a doctor over what he argued were just the effects of an old hockey injury. At first, he kept his illness secret from all but his wife, finally sharing the news with their three children and the Predators in 2004.
Medication worked well for years, and Peterson, with the Predators from the beginning as an assistant, stayed on the bench with Trotz. He also started his own foundation, raising money through golf tournaments here and in Canada for Parkinson's research at Vanderbilt University Medical Center.
Then Peterson found himself needing 16 pills a day. The side effects included little sleep, and the effectiveness of the medicine wore off more and more quickly. Working through an 82-game NHL season with the constant road trips had its own challenges.
"I've seen him struggle when we've had tough travel trying to get off the bus, get on the airplane, not being able to sleep and taking 45 minutes just to put your shoes and your socks and pants and your shirt on," Trotz said. "And having to get up two hours before everybody else just so you can be ready. What anybody can do in 15 minutes, it was taking him hours."
Last February, Peterson fell on the ice during practice and was forced to the bench. The associate coach who had turned down offers from friends around the NHL to join them moved to a new job as Nashville's director of hockey operations in June.
"It's a resource we've never had before, so why not have that resource in one of the people who's been here since day one, one of the best hockey guys in the business, one of the most loyal guys I've ever dealt with?" general manager David Poile said.
Peterson's wife kept trying to persuade him to consider DBS. The procedure now helps treat Tourrette's, obsessive compulsive disorder and is being studied for use in depression, epilepsy, substance abuse, obesity and headaches. More than 80,000 implants have been performed worldwide, and Vanderbilt handles more than 100 patients a year since its program began in 1998.
Finally, Peterson agreed to be tested to see if he was a candidate.
That meant performing agility tests both with, and without, medication, and Peterson said he learned it was "no way to live" without them. He went through four separate surgeries at Vanderbilt between Thanksgiving and Christmas with him awake for the second to respond to doctors in a process akin to getting a pair of eyeglasses.
Dr. Peter Konrad helped found Vanderbilt's DBS program and said doctors pinpoint probes to the areas affected by the disease once drug therapy becomes less effective, usually after five to seven years. Probes attach to wires that run under the skin behind the ear to a battery placed just below the shoulder blade, electrically stimulating the brain similar to a pacemaker for the heart.
The toughest moment came just before Christmas, when Peterson returned to have the device turned on. Off medication, Peterson needed his wife and daughter to dress him because the Parkinson's locked up his muscles, leaving him rigid and in excruciating pain. It was so bad that Peterson told his daughter he couldn't go on living if the procedure didn't work.
Peterson shuffled slowly into the doctor's office, and the doctor turned on the stimulator with a remote testing Peterson's right hand first.
"I'm like, 'Doc, what's going on?' My daughter started crying, 'It's not working Dad,'" Peterson recalled.
The doctor switched to Peterson's left hand, allowing him to immediately flex and move all his fingers. Then the doctor told Peterson to get up and walk. He did just that and had movement in his right hand 90 minutes later. Since then, he's been off and almost impossible to pin down, able to travel by himself and not needing help anymore.
Through it all, Peterson let Vanderbilt document each step and talked with local TV stations to publicize the procedure, even when his wife asked for a break when doctors placed the battery in the third surgery.
"He said, 'This is not the way we're doing this,'" Tami said. "'We're showing from beginning to end.' He got right on me."
Balance issues remain, so Peterson will not return to the ice as a coach. He's grateful the team kept him around with health insurance paying all but part of the estimated $132,000 in costs. His foundation is trying to raise enough money to pay for someone else to have the procedure.
"If we can help one person in the next year, it's great," Peterson said. "That's worthwhile."