Barker had eight points (three goals, five assists) and 24 penalty minutes in 23 games with Texas of the American Hockey League this season.
The Winnipeg native has 94 points (21 goals, 73 assists) and 286 penalty minutes in 296 career NHL games with Chicago, Minnesota and Edmonton.
On the international stage, Barker has helped Canada to two gold medals at the world junior hockey championship (2005, 2006) and gold at the 2012 Spengler Cup.
The six-foot-three, 222-pound defenceman was originally selected by the Chicago Blackhawks third overall in the 2004 NHL draft, behind Washington's Alex Ovechkin and Pittsburgh's Evgeni Malkin.
Barker missed most of last season with an ankle injury that required surgery.
"I had a tough year last year," said Barker. "I was out for four months, but it's behind me and I feel completely healthy now. I'm ready to go."
His signing was not a surprise, because he skated with Canuck players during informal workouts at UBC late last week, but said the deal was not completed until Sunday morning.
"It helped to come in early and, maybe, get to know some guys," Barker said. "I feel a bit familiar. So I think that was a bonus, for sure."
Before injuring his ankle with Edmonton, he was limited to 52 games in 2010-11 because of a back injury suffered while playing for Minnesota.
"It's tough," said Barker of the adversity he has faced the past two seasons. "You learn a lot about yourself during that time. It's a long road back. If you asked me five years ago if I would have been playing games in the (AHL) or trying to get back to that point where I was, I never would have imagined that. But I think it’s made me a better person, and I'm able to deal with a lot more now. I definitely appreciate (playing in the NHL) a lot more. I’ve worked hard to get to this point."
Barker, who expects to play an offensive-defenceman role, suggested his uniform changes over the past three seasons do not reflect his true value as a player.
"It's tough to gauge someone when they're injured and they're not playing or they're not playing enough," he said. "Obviously, I know where I want to be at in my head, and I know what I'm capable of. It might be different to what some people think of me now, but I've got to prove people wrong, play hard from the get-go, and just keep building on that."