Throughout the Bruins training camp, you could throw a net over the middle tier of B’s defenseman about who would project to be No. 3 or 4 or 5.

No. 1 and No. 2 were a lock with Zdeno Chara and Dennis Seidenberg — respectively.

After the trade of Johnny Boychuk to the Islanders the day before the first game, the argument for Torey Krug or Dougie Hamilton in the No. 3 or 4 slot had room for more than one beer.

When Chara went down with a knee injury last week, the debate now surrounds who is the No. 2 defenseman on the Black-and-Gold roster.

The 21-year-old Hamilton, the Bruins first-round pick at No. 11 overall in the 2011 draft as part of the 2009 Phil Kessel trade with Toronto, is staking that claim as he slowly develops into the role of prototype defenseman.

While Hamilton remains removed from wearing a “shutdown” label, the 6-foot-5 and 212-pound Toronto native has made great strides this early in the season in shutting down any question that he is now a top-tier blue liner on a team that traded Boychuk, then lost Chara and Kevan Miller, leaving the team quite “D”efficient.

Hamilton, however, is stepping up in a big way.

And out of the shadows of teammates like Chara and Seidenberg, and last year, Jarome Iginla.

“I still look up to those guys and the guys that are the best in the league,” Hamilton told Bruins Daily after Tuesday’s practice. “I learned a lot from [Jarome] about how much he kept improving. A guy with that many goals and that much experience is still trying to get better everyday. It taught me you can’t get satisfied with what you have. You can see that with the best players.”

For Claude Julien, the “shadows” factor is, well, a factor in Hamilton’s growth.

“Coming into our lineup as a 19-year-old and seeing Jarome Iginla who he probably watched as a kid; Jarome was probably in the Olympics when Dougie was a 10-year-old,” Julien said Tuesday morning. “Now Zdeno is his partner and you’re kind of in awe. Until you get over that little hump playing with and against players you idolized growing up it does make a difference.”

“I played with both [Seidenberg and Chara] for long periods of time, so there’s no difference in being easy to play with both of them,” Hamilton said.

With 117 games under his NHL belt, Hamilton has 46 points and a career plus-29.

More important under that belt is the added poundage from his draft weight of 199. And it is showing in more ways than one.

“He’s a lot more physical standing up to people a lot better than the past,” Julien assessed.

“I think it’s exciting for me to know I’m still not fully developed,” Hamilton said. “So I have a lot of room to improve with my body. But I do feel I’ve gotten stronger and faster since I’ve got here. That’s helping and my confidence comes from being around this city and this room. That makes you more comfortable and now with this bigger role.”

That role was front and center – and big — Saturday in the Bruins 4-1 win in Toronto before many family and friends. Hamilton had a goal and two assists, with a plus-3 rating in 22:31 of ice time.

“He just pounced on it – that’s a great read and reaction,” Julien said about the goal. “A great play on his part.”

Last week, Hamilton potted the game winner in Buffalo.

“Nice to get some points,” Hamilton smiled about his complete-game performance Saturday, “but I think I played a lot better defensively.

“Keep it going and keep trying to do that.”

Tuesday night against the Wild, Hamilton kept it going with 11 shifts and 10:20 ice time – in the first period alone. By game’s end a career-high 28:32, highest across both teams that included the Wild’s arguably No. 1 or 2 defenseman in the league in Ryan Suter who posted a 28:16 total.

While Hamilton was held scoreless in the Bruins 4-3 meltdown after taking a 3-1 lead into the third frame, his minus-1 was complemented with three late-game shifts in which he nearly tied the game on two occasions.

“I was playing a lot,” Hamilton said postgame. “I think I play better when I play more. You got to be ready when your name is called.”

Dougie Hamilton will be playing a lot more.

“He’s a player right now I talk about [with] confidence,” Julien said about his rising talent.

See what the Bruins had to say following their loss to the Wild on Tuesday night