BOSTON

The Boston Bruins rookies opened camp at Ristuccia Arena at noon Wednesday. Being rookies, they had to wait their turn for ice time.

Prior to the kids’ session, the veterans hit the sheet for one of their informal pre-camp twirls. Included among the varsity group were David Krejci, Milan Lucic, Brad Marchand and Dougie Hamilton. They are four of the five home-grown Bruins (Patrice Bergeron is the other) who will be on the 2013-14 roster. Every other projected Bruin arrived in Boston via trade or free agency.

Their in-house reinforcements, to say nothing of replacements, may be a long time in coming.

The top projected impact players in Wednesday’s group were Ryan Spooner, Jared Knight, Alexander Khokhlachev, Zach Trotman and Malcolm Subban. Spooner and Knight, both from the Class of 2010, are the closest to NHL-ready. Spooner is a quick, skilled and a creative center. Knight, who lost most of his rookie season because of a hamstring injury, shed 15 pounds during summer training in Ottawa.

They may be future top-six NHL forwards, top-four defensemen and No. 1 goalies. But it’s unlikely they’ll reach those designations this year, and perhaps not next season, either. Spooner, Knight, Khokhlachev and Trotman are second-year pros. Subban concluded his junior career last season.

The home-grown crew that should have preceded the Spooner group has been slow to arrive.

The Bruins have not accumulated assets in relation to their success. The 2007 draft is close to a complete washout. Zach Hamill, the No. 8 overall pick, is with his fourth NHL organization (Boston, Washington, Florida, Vancouver). Their only remaining prospect is former Boston College defenseman Tommy Cross. Last season, as a first-year pro, Cross didn’t make the Providence roster out of training camp.

Denis Reul, Alain Goulet, Radim Ostrcil and Jordan Knackstedt are not in the organization.

The 2008 draft hasn’t produced any keepers either. The Bruins shipped first-round pick Joe Colborne to Toronto in the Tomas Kaberle trade. Without Kaberle, the Bruins might not have won the Cup. Colborne, 23, is fighting for a varsity spot with Toronto.

The concern is not now or next season. The worries begin after 2014-15. By then, Chara will be 38 years old, most likely ready to cede some of his strongman shifts. Krejci, Boychuk, McQuaid, Paille and Campbell will be eligible for free agency. Krejci is a lock to be re-signed. The fate of the others depends, in part, on whether the Bruins’ next wave will be ready for NHL employment.