When Duncan Siemens first stepped foot in the Colorado Avalanche dressing room, he was about 190 pounds of shyness and uncertainty. The Duncan Siemens of Tuesday morning was 220 pounds of make-my-day certitude, a man who has been through the jaded early steps of the pro hockey business and ready to finally make his mark with the varsity club.

A first-round pick (11th overall) in the 2011 NHL draft, Siemens was supposed to have been a regular NHLer by now. Instead, he’s still only got four measly games of NHL experience on the resume, at the tail end of last season with Colorado. Many wondered if that would be it for Siemens and the Avs, a case of a first-round pick gone bad. Injuries, coaching changes, different organizational philosophies about what kind of player he should be – it all produced a toxic stew of underachievement for the 6-foot-3 defenseman.

But here’s what has changed: Siemens was told by the team at the end of last season that it was going younger, in all areas, and that it wanted him to still be part of the mix. He was given a qualifying offer and a mandate: Hit the gym hard, put on some more muscle and come to training camp ready to kick some ass. And, work like a demon on handling the puck.

And that’s what he did, and what he’s done so far in camp. Tuesday night against the Vegas Golden Knights, Siemens will be in the lineup, ready to show the coaching staff finally – finally – he’s ready for a full-time NHL gig.

“If I stay within myself, I think good things will happen,” Siemens said. “If I try to be something I’m not, that’s when I start making mistakes. I’ve just got to go out there, be hard, be mean, be heavy. That’s the side of my game that’s really strong and that’s what I’ve been looking to do throughout camp. I think the game has changed so much from my first year until this, going into year five. I think you have to be able to contribute in all areas and be able to give the forwards another option, and I have to do that. But that doesn’t take away from what’s gotten me this far, and that’s being heavy and physical.”

Siemens thought he could play that way when he first came to the Avs. He’d done it easily as a junior player in the rugged WHL with Saskatoon, after all.

“But the big thing was, at 18, 19 years old, not knowing just how strong and how big guys are here,” Siemens said. “Coming from junior, where you’re one of the biggest guys coming in against guys who are just as strong, if not stronger. Now, just having the extra weight, having the extra experience, knowing what guys are going to come at you with, what they’re going to try and do, now I think I know better what I have to do, what my job is. I’m not out there to hurt anybody, but I’m out there to let them know I’m coming.”

Here is the lineup for tonight’s game: