The left-handed defenseman was taken 18th by the Stars on Friday in Vancouver.

The 17-year-old defenseman was asked to step up and play the top minutes for Mississauga, a difficult task which forced the 6-foot-3, 193-pounder to take his game to the next level. That helped the Steelheads to a spot in the playoffs and helped Harley to a spot in the first round of the NHL Draft.

VANCOUVER, British Columbia -- Thomas Harley was put in a tough spot last season, but it turned out to be a good spot.

"To be put in that position and then excel as a 17-year-old, that says a ton about him," said Joe McDonnell, the Stars' director of amateur scouting. "The more they gave him, the more he got better as the year went on. We really like him."

Harley is a longer-term project who will go back to Mississauga and continue to improve, but he gives the Stars the kind of defensive depth you need to build a strong organization. Dallas got a blue-chip defenseman in Miro Heiskanen in 2017, but 18 of their past 20 picks before this draft were not defensemen.

Thomas fills a real need.

Stars general manager Jim Nill has just four picks in this draft, so he was hoping to possibly move back from the 18th pick and try to add an extra pick. When that didn't develop, Nill said Harley was an easy choice.

Video: Stars draft D Thomas Harley No. 18

"We had a couple of calls and a couple of discussions, but when that didn't pan out, he was the player we wanted," Nill said. "He's a really good skater, a leader for his team, and we think he's only going to get better."

Harley played 62 games in his first OHL season and tallied 15 points (one goal, 14 assists) in 2017-18. Given about 28 minutes a game in his second season, his numbers went up to 58 points (11 goals, 47 assists) in 62 games in 2018-19.

"I had a great season. I was No. 1 (defenseman) in Mississauga and I played 28-29 minutes every night," Harley said. "I played a lot and I think I learned a lot."

Harley said he sees himself as a two-way defenseman who had to face the opposition's best line every night. He said he also likes to skate and find open ice when he can.

McDonnell said he'll be interested to see how Harley improves in the coming years.

"I think maybe people said he didn't have the jam that they would like to see, but I think a lot of that was because of the minutes," McDonnell said. "He has skill and I think he learned to manage games and conserve his energy so he could play 30 minutes. He's a smart player."

Harley said he learned to love the minutes, and that a changed personality helped in the process.

Video: Harley excited, relieved to be selected by Stars

"I think I was super emotional as a kid and just got out of control at times, and now I've gone to the other extreme," Harley said. "It does help me out there. I see guys chirping out there and I just laugh. It doesn't bother me at all."

And that's one of the reasons the Stars coaches liked him so much.

"He doesn't get overexcited with the puck, saves his energy, paced himself," McDonnell said. "Obviously, at his age, he still has a lot to learn and a long way to go. But he has a good upside and a good future."

Harley said that's one part of the business, he will have to learn. Asked when he might be ready, Harley chuckled.

"My ego says next year, but I'm not sure that's actually going to happen for me," he said. "I hope it does."

The Stars will be fine if after his 18th birthday on August 19 he goes back to the OHL, has a great year, and plays in the World Junior Championship for Team Canada (he played for Canada in the Under-18 World Juniors last season).

That would be a great next step.

This story was not subject to the approval of the National Hockey League or Dallas Stars Hockey Club.

Mike Heika is a Senior Staff Writer for DallasStars.com and has covered the Stars since 1994. Follow him on Twitter @MikeHeika, and listen to his podcast.