The Rangers’ 3-1 victory on Tuesday night over the Canucks that extended the club’s lead for first-round home ice while reducing the playoff clinching magic number to three points may have come at a heavy cost. For Ryan McDonagh — the Blueshirts’ best skater throughout the season and their most valuable other than Henrik Lundqvist — left the ice with an apparent left shoulder injury and in visible pain after taking a wicked hit into the rear boards by Alexandre Burrows with 43.8 seconds remaining in the contest. “It’s not serious,” a Rangers spokesman said, referring to the initial diagnosis for McDonagh, who left the building with his left arm in a sling. Nevertheless, the defenseman received treatment for an extended amount of the time following the match, and the Rangers already have lost Chris Kreider for an indefinite period to a left hand injury. After being remarkably healthy most of the year, the Rangers cannot afford to be without McDonagh for any significant stretch. “You get worried,” said Lundqvist, steadfast in the face of relentless Canucks’ traffic and pressure throughout the first 50 minutes of the match. “We have important weeks ahead of us — hopefully months — and it’s important that we’re healthy. “Hopefully it’s not too bad.” McDonagh, who was in the process of retrieving the puck, was first hit by Zack Kassian on the left before Burrows nailed him from the right, blindside. Burrows received a five-minute elbowing penalty and game misconduct. “It’s not a good thing to see him laying on the ice,” Brad Richards said. “But he’s resilient and battles through a lot. Hopefully it’s short-term and nothing serious.” The Rangers’ victory, their seventh in the last eight games overall, established a franchise record for wins on the road, this one in the Alain Vigneault-John Tortorella matchup behind the bench in their league-leading 25th away from home (25-14), with two more to go including Thursday night’s match in Colorado and the season finale at Montreal on April 12.