After spending 18 years in the major leagues with the Expos, Rockies and Cardinals, Walker is on manager Tony La Russa's training camp staff.
"I don't know if someone caught wind of it or not," Walker said. "But I mentioned it to a couple people. Tony called, we talked for a little while. The subject came up and he said, 'If you want to come out, come out.'"
The Cardinals' former right fielder now makes his residence in Florida and plans to split time between the Cardinals' clubhouse and helping out at home this March.
"I told Tony it won't be an everyday thing," Walker said. "My wife's going to need some help with the kids before and after school, and I don't want to drop everything on her. I want her to have a life as well."
Walker briefly thought about playing this season.
"I did a bunch of loading up of some wood at our house in Wisconsin," he said. "I was picking up wood and throwing it, kind of similar to a baseball swing. The next day I was in my neck brace again, so right then and there, I was like, OK, I can probably get this thing fixed, but my time's up. It's up physically and it's up mentally."
He will also be an assistant coach for Canada during the World Baseball Classic, which runs from March 3-20.
"I'm really disappointed," he said. "I told them I've been playing for 20 years. How come you didn't come up with this sooner? I'm still grateful I get the honor to put my country's name on my chest as a coach. That's the way it has to be. I would have loved to play. Although if I had played, I would have really thought more about playing another year in the big leagues."