SAULT STE. MARIE, Ontario — The boos started before Don Sweeney spoke a word. The Bruins general manager leaned down, without pause, and for the third time that day, called out a name. There was conviction in his voice. It was in no one else’s. The silence on the broadcast, in comparison to the unrest in the BB&T Center, site of the 2015 NHL Draft, lasted a few beats.

The kid stood, his face bearing just the hint of a smile. He hugged his father, who looked stunned. His mother had been convinced that instead of Sweeney at the podium, it would be NHL commissioner Gary Bettman striding up to announce a trade. She thought the Bruins would deal downward, moving later in the first round, where her son would be more comfortably selected.

That didn’t happen. The No. 15 pick in the 2015 draft would be 18-year-old Zach Senyshyn, who had no idea what was coming.

“It was the best day of his life,’’ Melissa Senyshyn said, “followed by the worst day.’’

.   .   .

He had anticipated this since he was 6 years old, since he raced every other child on the ice — and beat them all. Since he convinced a non-hockey family to become one in the service of a dream so unrealistic that his parents couldn’t always fathom that he was dreaming it.

There was little celebration of his NHL prospects in the Senyshyn household. His parents hung a chart on a bulletin board in their Ottawa house showing how many kids got weeded out at each level of hockey, with fewer and fewer surviving each jump, the fewest still reaching the NHL.

“Not to make him feel bad,’’ his mother said, “but to make him realize . . .’’

“Just to instill me with a lot of confidence,’’ Zach interrupted. He smiled, clearly ribbing his mother. “Your dreams can come true.’’

They didn’t want him heartbroken. He never thought he would be.

“That was his attitude all along,’’ Melissa said. “He just dismissed it. He was like, ‘You guys are nuts, I’m going to the NHL.’ We were like, ‘All right, honey.’

“We just kept humoring him generally and then all of a sudden when his name was called, he kind of looked at me, like, ‘Told you I was going to go to the NHL.’ ’’

Immediate backlash

At the time Senyshyn was selected, the Bruins were in the midst of a 24-hour transformation. They traded Dougie Hamilton. They traded Milan Lucic. They tried to move up in the draft to select a surefire defenseman of the future. They couldn’t.

They were left with three consecutive picks in the first round, Nos. 13, 14, and 15.

Jakub Zboril.

Jake DeBrusk.

Zach Senyshyn.

None of the picks seemed immediately popular, but Senyshyn was the biggest question mark. The right wing was a reach, chosen with more high-profile names (Mathew Barzal, Kyle Connor) still on the board.

He was the 38th-ranked North American skater. His previous ranking was 56th. He wasn’t even listed in the September draft guide.

The backlash was vicious, making a moment that Senyshyn had dreamed about into one that became, in his word, “bittersweet.’’ He had to take steps back from social media, erase the hurt, shield his parents, realize that the passion that caused the uproar was the same passion he hoped would support him later, as a Bruin.

He took comfort in having two others who knew what it was like in Zboril and DeBrusk. A friendship formed.

They knew what he was going through. They understood. They felt it, too, though not as much as Senyshyn. They helped him, as he put it, “kind of weather the storm a little bit sometimes.’’

Then all three failed the Bruins’ conditioning test. They went out to dinner that night, Sept. 10, at the Cheesecake Factory. As DeBrusk recalled, “I even said to those two, like, this could blow up. Just where our spots are and what can happen, and the next thing you know, there it is.’’

They looked up, and there they were on the TV screen, the news of their failure blaring out at them.

“But that’s just how it goes,’’ said DeBrusk. “It’s a lesson for us, and a lesson that we’ll never forget, that’s for sure.’’

“We’re like, it’s a different game now,’’ said Senyshyn. “We’re really under a spotlight.’’

A lot of traits to like

All has calmed down now, months later, as Senyshyn and his parents sit in the house that Melissa and Paul rent when they visit Sault Ste. Marie, where Zach plays for the Greyhounds of the Ontario Hockey League. There are Valentine’s Day decorations in the kitchen, and gluten-free oatmeal cookies on the coffee table.

Two nights earlier, Senyshyn had made a slick move to evade defender Jakob Chychrun of Sarnia — himself a top prospect — before whistling the puck into the back of the net for his 33d goal of the season, tied for seventh in the league.

This season, Senyshyn has gotten more ice time and more responsibility after scoring 26 goals and adding 19 assists in 66 games last year, his first in the OHL. He was just named the 46th-best NHL-affiliated prospect by TSN, the only Bruin listed.

“He’s probably one of the most fluid skaters I’ve seen in a long time, as far as his size at 6-2 and being able to accelerate as quickly as he does through traffic,’’ said Jack Higgins, the head scout for Central Canada for ISS Hockey and a former Bruins amateur scout. “Plus he’s an awfully smart two-way player, so he fits right into Boston’s type of players.’’

Senyshyn’s scoring touch, speed, and smarts aren’t in question. As Drew Bannister, the Greyhounds coach, said, “You could probably put him in the NHL right now and he wouldn’t look out of place skating-wise.’’

He has the fearlessness, too — multiple people called it “recklessness’’ — to cut to the net, to create space.

He still needs to make strides in other parts of his game: his play without the puck, his inconsistency shift to shift, his physicality. He needs to understand, as Bannister pointed out, that he won’t always be able to beat a defender wide one-on-one. He needs to fill out his 192-pound frame.

“When he has the puck on his stick, it’s like go, and then you notice him,’’ said Bannister, a former NHL defenseman. “He needs to be noticed more away from the puck, so that he has the puck more on his stick.

“That’s something that all young kids — not only Zach — at this level don’t understand is the harder they work away from the puck, the more time they’ll spend with the puck.’’

That will help him create more offense, for himself and teammates. That — among other improvements — will help him round his game into where it needs to be at the next level. That will help the Bruins justify that No. 15 pick.

“Guys that have that explosive ability, they’re always going to be coveted in the National Hockey League,’’ Sweeney said. “We just felt that a lot of people thought we had stepped up in that situation and we probably acknowledged we did as well.

“But we would be kicking ourselves had we not taken him there hoping we’d get him with our second-round [pick] and somebody jumps in front of us.’’

Itching to move up

The junior hockey experience in the Soo has been good to Senyshyn, has developed him, encouraged him, given him a home. But if Senyshyn gets his way, he won’t be back for a third year in Sault Ste. Marie.

He’ll be in Boston.

“I really . . . I want to make the Bruins next year,’’ said Senyshyn, who turns 19 in March. “Last year it was . . . a really exciting experience, but this next camp I’m definitely coming to make the Bruins and I’m going to do anything, anything I can to get there. I’m pretty determined.’’

Asked if that was realistic, Senyshyn said, “I think with my capabilities and my speed and my talent, I think that if I can add some of these things to my game, I think I can definitely be a Boston Bruin next year.’’

That, of course, is well ahead of what his coaches expect. It’s even ahead of where his parents might like to see him, given the size and speed and strength of players he would be going up against.

“I’ve always said the player is going to dictate,’’ Sweeney said. “I think you never want to rush. You never want to be impulsive with putting a player in there before he’s ready. [David] Pastrnak represents a good example of that.

“But when a player is, and can help your hockey club, you have to give him his credit.’’

While next season might seem a bit premature, Senyshyn knows what he wants. He wants Boston. He wants the NHL. He wants to prove not that all those voices and tweets and criticisms were wrong, but that Sweeney and the Bruins were right.

“My favorite thing in the world to do is score goals,’’ Senyshyn said. “And when I see that opening, when I see that light at the end of the tunnel, see I’m going to be able to get even a glimpse of trying to get that goal, I’m going to do everything I can to get to that area and score that goal. That’s what I want to do for the Bruins, is score goals.’’

And if that happens, as he hopes and he expects, then all the worries about where he was drafted, all the insults and hatred, will all just fall away. The best day, which became the worst day, will become the best day again.

Watch video of Zach Senyshyn on BostonGlobe.com. Amalie Benjamin can be reached at abenjamin@globe.com.