The Vancouver Canucks have relied on their depth throughout the regular season and into their post-season run.

That key element of the team's success could be tested in the Western Conference finals with defencemen Christian Erhoff and Aaron Rome both questionable for Sunday's Game 4 in San Jose against the Sharks.

The Canucks called for reinforcements, bringing up rookie Chris Tanev after Erhoff and Rome left Friday night's game with injuries.

Erhoff took a hit in the first period from the Sharks' Jamie McGinn, and Rome was helped off the ice in the final nine minutes of the match, also after a hit from McGinn.

Vancouver coach Alain Vigneault was unwilling to divulge his plans for the Canucks blue-line, though he said Tanev was brought to San Jose so the team could have seven healthy defencemen.

"One of the things that we have given ourselves is more depth on defence," Vigneault said. "We've worked at making sure guys who weren't in the lineup were staying ready. They know at one point or another we might need them."

Tanev, who plays for the American Hockey League's Manitoba Moose, has never appeared in an NHL playoff game. He has yet to hear anything official from the Canucks, but making the trip has to mean something.

"I'm here, we'll see what happens," Tanev said. "I'm here to help the guys."

Erhoff and Rome were not at Sharks Ice -- San Jose's practice facility and the site of Saturday's brief workouts. Then again, Sami Salo, Ryan Kesler, Kevin Bieksa, and Maxim Lapierre were also no-shows.

"Whoever we use, I'm confident they're going to do real well for us," Vigneault said. "We've dealt with injuries and we've been able to handle it well."

Sparingly-used veterans Andrew Alberts and Keith Ballard could see some ice time. However, Alberts hasn't played since May 3 and Ballard has appeared in a combined five games during the first two playoff series.

"It's been the same story all year," Ballard said. "We have to use our depth and if it happens I'm excited to get back in. When two guys that have been playing well go down, it's not the ideal situation."

Ballard has been watching the action lately from a seat in the press box, even though he's healthy and says he's prepared.

"I have to play well if I get the chance," Ballard said. "I've had a lot of ups and downs this year and I don't think I've been nearly as consistent as I need to be."

If Ballard does see the ice, it only means the Canucks are running out of defenders. Vigneault said it could be Ballard's opportunity.

"He probably has an opportunity to step in and show us what he can do," Vigneault said. "We're confident he'll be good if we need him."

Tanev, meanwhile, was rushed to the Bay Area for Saturday's practice. He arrived just in time to get a nice workout.

"It's playoffs so it's faster, it's tougher and it's more physical," Tanev said. "But I am definitely confident. If I get the chance, great, but if not I'll be rooting the guys on."