When Andrew Nielsen was selected in the third round of the 2015 NHL Draft by the Toronto Maple Leafs, it came as a surprise to many. More highly touted names, such as Guillaume Brisebois, Mitchell Vande Sompel, Blake Speers, and Aleksi Saarela were still on the board.

Instead, the Leafs, led by Mark Hunter, selected Nielsen, a WHL rookie who had already missed his draft year when he stay back and played midget rep hockey.

Nielsen, a relative unknown out of a Lethbridge Hurricanes organization that isn't known for producing many NHL prospects, was a big kid who could shoot.

A year later and Nielsen has joined the Toronto Marlies after finishing third in WHL scoring alongside first rounders Travis Sanheim and Ivan Provorov, both of the Philadelphia Flyers, with 70 points (18 goals, 52 assists), in 71 games.

After losing in the first round of the WHL playoffs, where he registered three points in five games, Nielsen played in five games with the Toronto Marlies down the stretch.

And while Marlies head coach Sheldon Keefe doesn't expect to use Nielsen in the playoffs, he's happy with the way the 6-3 defensemen has progressed early on in his pro career.

"He’s a real good shooter, you can see why he was able to generate the points and the offence he did in the Western Hockey League," Keefe said after the Marlies' 4-2 win to end the regular season.

Even Nielsen didn't expect to progress so quickly.

"I didn't overly expect it, I kind of came in knowing I wanted to put up more numbers," Nielsen, who registered an assist after carrying the puck confidently deep into the offensive zone on Jordan Hickmott's first AHL goal. "I didn’t think I was going to put up the numbers that I did but it was good to do what I did and have the success that I had."

His experience with the Marlies early on, despite struggling defensively (he gave up several quality scoring chances and a couple of odd-man rushes on poor pinches in the game while playing big minutes with veteran Dave Kolomatis) at times, has been nothing but positive.

"It’s been fun just learning lots, coming to the rink every day and just taking everything in," he said. "It’s been good."

Nielsen credits the Marlies for providing their young players with an open dialogue and points to Marlies defensemen Connor Carrick as a mentor.

Carrick is staying in the same hotel as Nielsen and they have spent a lot of time together.

"He’s a really knowledgeable guy, he’s played a lot of NHL games, he’s played in Washington, he’s played with guys like John Carlson and Karl Alzner and he says he watched them and tries to bring their games to his and he just thinks the game so well," Nielsen, 19, said of his 22-year-old teammate. "You can always pick his ear about hockey. It’s been nice to have somebody like that."

On a couple of plays, including his assist, it looked like the mentorship from one of the Marlies' more gifted offensive defensemen paid off.

Midway through the first, Nielsen slid in off the point and took a risk to win a footrace and get a shot off.

Later in the game, he stepped around Georgio Estephan with a deke to find Mason Marchment cross-ice with a nice pass.

"I think he’s played well, I think today was perhaps his best game," Keefe said of his talented young defensemen. "He really showed some ability along the offensive blueline to get some pucks towards the net, to get some shots off."

As the only teenager on the Marlies backend, the path has just begun. Now it's time to train and practice as his teammates pursue a Calder Cup.