Three games into Bo Horvat’s NHL career, his coach threw him right into the fire.

The Canucks were getting blown out at the Staples Center that night in November 2014, with the defending-champion Kings up three goals after the first period. At some point, Vancouver coach Willie Desjardins decided he’d seen enough of his stars matching up against L.A.’s high-powered top line.

“I thought I might as well put Horvat on [Anze] Kopitar and he played really well,” Desjardins told The Post in a phone call Tuesday. “That was the game that showed me he could really play. And after that his minutes went up quite a bit.”

Even then, no one quite expected Horvat to become what he is now. The 27-year-old center, who was dealt to the Islanders on Monday night in the first blockbuster of the NHL season, has turned into a star-caliber player, having already crossed the 30-goal rubicon 49 games into his season. He’s expected to help fill a scoring void that’s been plaguing the Islanders all season and help key a playoff push that, if successful, can bring postseason hockey to UBS Arena for the first time.

Horvat’s rise to Canucks captain to star was no accident. When he first arrived, Desjardins was worried that he wouldn’t be a good enough skater to stick in the league. Now, that is listed among his better skills.

“He is an elite skater now,” Desjardins said. “Very seldom do you see somebody change that much at that age. And the thing lots of people ask me is why that happened.

“I think the biggest thing I can say about Bo is that he wouldn’t accept being average. He wouldn’t accept being an average hockey player. He wanted to be a player that you could count on, he wanted to be a player who could play big minutes, so he found a way to improve his game. I think that’s probably the thing that captures him the most.”

Indeed, Horvat’s productivity has steadily risen since he broke into the league. Last season, he set a career high of 31 goals, a mark he’s already tied at the All-Star break. With 54 points, he’s also on pace to easily surpass his career high (61).

“You look at the number of tip-in goals he has this year and the number of wrist shot goals he has this year and you watch the way he’s shooting the puck this year compared to the past few years and it’s off the wrong foot sometimes,” John Garrett, the color analyst for Canucks games on SportsNet, told The Post. “Every year it’s, ‘Well what am I gonna work on this summer?’ And then he comes back to camp and sure enough he’s made that little improvement.”

Recently, Horvat started working with Adam Oates, the Hall of Fame center turned private skills coach. On his introductory call with the media after being dealt to the Islanders, Horvat quickly credited Oates for his offensive rise.

“I think a lot of it is just going to the right areas and putting myself in positions to score those goals and make those plays,” Horvat said. “He’s helped my game a lot and especially over the last couple years, just giving me feedback. … I like to think I worked hard this summer and I think it’s paying off.”

Oates himself said it wasn’t a matter of major changes to Horvat’s game so much as getting better at smaller details they’ve worked on together.

“He’s a very fast guy, he’s a great skater,” Oates told The Post. “When I first thought of Bo, I thought of great skater, breakaway guy. Really good on the power play in the middle. Really good. So we talked a little bit about, is there more plays? Can you make more plays? Where do you get more plays? Can you incorporate your linemates a little better? When do you actually play a little slower?

“Because for example, in transition, the game’s fast. In [the offensive] zone, the game’s not necessarily fast. There’s 10 bodies in there, right? So, when do you skate fast, when do you slow down? And quite honestly, we just sort of talk like that. That’s all we do, and trying to recognize in the course of a game what the particular situation is.”

In Vancouver, Horvat — who replaced Henrik Sedin as the Canucks’ captain — was lauded for his character off the ice and in the dressing room. Oates quickly saw that working with him.

“The one thing about hockey … we have an underground, right? Everybody knows guys on other teams, everybody talks about guys, everybody knows everybody’s agents, there’s an underground communication,” Oates said. “Everything you hear about him is fantastic. And when I met him this past year, fantastic.”

That fits the mold of a Lou Lamoriello player, and someone who can get along well in the Islanders’ dressing room, a group closely knit after multiple playoff runs. Horvat got to learn at the feet of Alexandre Burrows and the Sedin brothers in Vancouver. He’s dealt with subpar results with the Canucks, but according to those who know him, has the sort of habits that can propel a team forward. The numbers, of course, support that as well.

“He’s really a character guy,” Desjardins said. “I think the Islanders team, the best word to describe them is team. I think their leadership and coaching is outstanding. They formed a group that finds a way to play hard all the time and Bo wants to be part of that group.

“He’ll want to be part of that organization, he’ll want to win. It’s not about him. He’s not coming in where it’s all about him. He just wants to play and wants to win and whatever role he takes, he’ll do it. He’ll be a really good fit in that room.”