LAS VEGAS — The Colorado Avalanche will have Nathan MacKinnon — perhaps close to full strength, to hear coach Jared Bednar tell it — for Tuesday night’s must-win Game 4 of the Western Conference final.They’ll also have a new goaltender.Bednar is pushing the last button he has left, swapping in Mackenzie Blackwood for Scott Wedgewood as the Avalanche attempt to claw their way out of a 3-0 series hole against the Vegas Golden Knights. Blackwood hasn’t played since getting pulled after the first period of Game 5 in the second round.“I feel like if he’s loose and confident and playing his game, he has the ability to not only win us games but steal us games,” Bednar said. “We’re at 0-3 in the series, so it’s not a desperation move; it’s just, you’ve got to make a change and see if something else works.“We felt confident in both guys all year long. I felt like Wedge earned the net in (games) 1 and 2, and we gave him the shot in (Game) 3, and we didn’t get it done. It’s not on him, either; it’s on our team. But we’re just looking for Blackie to come in and play to the best of his ability and be loose and have fun. The whole team’s kind of in that mode right now, and if (he does) that, you might see the best of him.”