Gregory Campbell considers Mike Richards one of his better friends in the NHL. In 2003, Campbell and the ex-Flyer won the Memorial Cup in junior hockey as members of the Kitchener Rangers. Campbell praises Richards as being one of the more underrated players in the league.

But on Monday night, Campbell saw Richards hoisting the Stanley Cup after the Kings beat the Devils. That’s when it struck Campbell that the Cup was no longer under the stewardship of the Bruins.

“It hits home seeing another team lift the Stanley Cup,’’ Campbell said during a conference call Wednesday. “We considered it ours for a year. We worked so hard to get it. Now that it’s not ours anymore, it really hits home. Hopefully it allows us to get that hunger back and strive for it again next year.’’

Campbell and teammate Chris Kelly had their cracks at reaching the open market July 1. They could have earned significant raises, given the lack of experienced centers available.

But Monday, Campbell (three years, $4.8 million) and Kelly (four years, $12 million) re-upped with the Bruins. Both believe their current employer gives them the best chance to capture the Cup once more.

Kelly will officially sign his extension July 1. On that day, the expiring contracts of Brian Rolston, Joe Corvo, Greg Zanon, and Mike Mottau will give the Bruins the space they need to fit Kelly under the salary cap.

“It almost makes you get that sick feeling,’’ Kelly said of watching another team claim the prize. “It stings a little bit knowing that was us a year ago and how great that felt. We want that taste back.

“It is nice to have an extended offseason to mentally prepare and heal whatever bumps and bruises you have. But at the end of the day, if you’re playing into June, you and your team have done something right.

“That’s what everyone strives for. That’s the reason why Gregory and I signed back in Boston - for that opportunity to consistently play in the month of June.’’

Neither center has the impact of go-to Bruins such as Patrice Bergeron and David Krejci. But what they lack in skill, they compensate for with the specificity of their games.

Kelly is an experienced, intelligent, and dependable center whose hockey sense is rivaled only by Bergeron’s.

Campbell is the relentless fourth-line bulldog who can take faceoffs, kill penalties, and bang bodies in short, active spurts.

Kelly’s defensive presence and Campbell’s physical nature complement Krejci’s offensive touch and Bergeron’s complete game.

“Strength down the middle is critical to our team,’’ said general manager Peter Chiarelli. “We build from the back out. But right down the middle is critical. We saw it again this year in the playoffs with the grind you’ve got to go through to win. That’s why it’s critical to have strength down the middle and to have these types of players.’’

In 2012-13, Campbell should once again center the fourth line between Daniel Paille and Shawn Thornton. All three could have reached UFA status July 1. Thornton signed a two-year extension March 17. Paille re-upped for three years June 1.

Kelly projects to be the No. 3 center next season. Assuming first-line right wing Nathan Horton can overcome postconcussion syndrome, Rich Peverley will open the year on Kelly’s right side. The Bruins have yet to determine whether Benoit Pouliot, last season’s No. 3 left wing, will return. Pouliot will become a restricted free agent July 1.

Kelly and Campbell are the final UFAs-to-be the Bruins will sign before July 1. The Bruins have just under $64 million committed to payroll to 2012-13, including the salaries of Tim Thomas and Marc Savard.

Chiarelli reiterated that the Bruins are assuming Thomas will not play next season. Chiarelli has yet to speak with Thomas since the goalie - first via agent Bill Zito, then through Facebook - announced his plans to take off 2012-13.