VANCOUVER, Canada -- In the Ducks’ most significant game of the season so far, they will start a 20-year-old making his NHL debut in goal.

Rookie John Gibson, promoted from minor-league Norfolk on Saturday following a blow to the
head sustained by 19-win rookie goalie Frederik Andersen on Friday, left the ice first at the Ducks’ Monday morning skate at Rogers Arena in Vancouver and will start Monday night against the Canucks (35-32-11).

He replaces the team’s slumping primary starter, Jonas Hiller, who has lost three consecutive games -- including two to last-place Edmonton -- and is 6-9-3 since winning 14 straight games from Dec. 6-Jan. 12.

Asked how he'll know if he’s ready for this upgrade in competition, Gibson smiled and said, “Go out there and play, and I’ll let you know after.”

The game is crucial for the Ducks (50-20-8), who cling to a one-point lead over the San Jose Sharks for the Pacific Division lead with the Sharks coming to Honda Center for a Wednesday night showdown. Anaheim is also three points behind Western Conference leader St. Louis.

The Ducks have four games remaining, the Sharks three.

In Norfolk, Gibson was 21-17-4 with five shutouts. His goals-against average was 2.34 and his save percentage was .919.

Before that, he was in goal for Team USA when it won the gold medal in last year’s World Junior Championship in Russia; he was named MVP of the tournament.

Ducks 20-year-old defenseman Hampus Lindholm said he’s seen Gibson step up his effort in important international games, adding that the goalie ranked hockey’s No. 2 overall prospect is poised and skilled beyond his years.

“It’s going to be fun, been looking forward to it for a while,” Gibson said. “Any time you can help the team win, it’s an honor and I want to make the most of it.”

Gibson said he was informed of his start by Coach Bruce Boudreau following the Ducks’ 4-2 loss at Edmonton on Sunday, when Hiller allowed three second-period goals two nights after giving up four goals on nine shots in the first period of a 5-2 home loss to then-last-place Nashville.

“You just go in and play the way you usually pay, you don’t want to do anything different,” Gibson said.

Boudreau said after Sunday’s loss that “I think [Hiller’s] really lacking in confidence.”

Hiller, who’ll be a free agent at season’s end, is 29-13-7 this season, and was the starter in all seven games of the Ducks’ first-round playoff exit against the Detroit Red Wings last year.

Now he’s been replaced in this high-magnitude game by a rookie making his NHL debut, so his security as a playoff goalie is very much in doubt.

Boudreau has previously used different goalies in back-to-back scenarios such as this one, but the switch to Gibson still surprises. The rookie was with the Ducks for three games in January and never saw action.

Hiller “is deeply valued. I’ve said things to him this morning, and I’ve talked to ‘Gibby.’ We want to make sure that both our goaltenders know how important they are to the team,” Boudreau said.

On Monday, Hiller took extra practice at Rogers Center under the supervision of the team’s goaltending coach.

In Hiller’s defense, Boudreau also called the Ducks’ recent defensive play “spotty,” and “not good enough ... we seem to give up one or two bad goals a game, and if it doesn’t turn around, it’ll be a tough go.”

The absences of injured first-line defenseman Cam Fowler and tough blue-line player Mark Fistric have also hurt.