By Matt Dolloff, CBS Boston

BOSTON (CBS) — The Boston Bruins still want to be a playoff team. The head coach (and his system) is returning after two straight years out of the playoffs. The general manager has said the team doesn’t need a “major overhaul” and needs to be more patient with younger players.

In light of all that, the Bruins still need to make some kind of significant change to the roster, since that won’t be happening on the coaching staff or in the front office. If they want to return to the playoffs, some kind of major shake-up – depending on your definition of “major” – is imperative, and especially so knowing that the head coach, system and (most) core players are returning.

So where does GM Don Sweeney start? Here are four ideas that the Bruins should entertain, if not bring to fruition, this offseason if they want to get back to being a playoff contender without a major overhaul.

1. Acquire a No. 1 AND No. 2 defenseman

The hardest goal to achieve, yet the most vital to the Bruins’ success. Zdeno Chara can still be the captain, but physically can no longer be a big-minute stalwart defenseman playing against opponents’ top players. Kevan Miller never played like a top-pairing defenseman in the first place, nor will he ever.

Essentially, every defenseman on the team played minutes and matchups that went well beyond their actual talent levels. Adam McQuaid and Torey Krug can be fine complementary players and specialists on a third defensive pairing, but consistently get exposed playing top-four minutes. The idea should be to reinforce the top of the depth chart and slide everyone down into roles that better suit their abilities.

Unfortunately for Sweeney, the unrestricted free agent landscape for top-pairing defensemen in 2016 is thin – virtually barren in terms of No. 1’s. So he will need to make a big trade for a No. 1 defenseman, whether established or sure to become one in the near future. They could feasibly acquire a solid No. 2 defenseman on the free agent market, and they should have the cap space to do so.

In order to free up more space to add talent up front and on defense, Sweeney should also attempt to…

2. Trade Tuukka Rask

If the Bruins’ defensive system is predicated on making life easy for the goaltender, then why is the team allocating a $7 million cap hit to the goaltender? Tuukka Rask is one of the NHL’s more skilled netminders and has turned in Vezina-caliber seasons in the past, but to pay him the third-highest salary in the league seems counterintuitive to how Julien’s system works in the first place. With a weak defensive corps, one of the least talented in the league, in front of him, Rask turned in the worst season of his career.

So why is the team still paying Rask like a goalie who ought to cover up for a poor defense, but proved this past season that he could not? Rask has especially seemed to shrink in the biggest situations, culminating with his diarrhea-fueled tap-out in the Bruins’ season-ending 6-1 loss to the Ottawa Senators.

It’s time for the team to explore trading Rask, who should still have value to teams as a No. 1 goalie that would bring stability to the net and be under control for several years. It’s not a given that such a drastic move will happen, nor would it sink the Bruins if it didn’t – but a Rask trade is a distinct possibility in the wake of Rask’s subpar season and Sweeney’s refusal to commit to him as “untouchable.”

The Bruins could very well enter the 2016-17 season with Rask, but could stand to create the cap space and improve in other, needier areas of the roster. The free-agent market for goaltenders is quite thin, but would you rather have Rask and the current Bruins defense, or a stopgap goalie and a rookie Malcolm Subban with a legitimate top-two defensive pairing in front of them?

3. Upgrade/replace players at key positions on offense

Patrice Bergeron may be the only Bruins forward who is truly “untouchable” in any kind of trade scenario (but don’t tell that to Felger & Mazz). But, assuming Brad Marchand also stays, then the Bruins have a lot of work to do to change the mix of forwards – because this past season’s mix clearly isn’t working.

The cap space gained from Loui Eriksson’s departure could theoretically go to a contract extension for Marchand. David Krejci could still be a valuable trade chip, but assuming he sticks around and continues to play with David Pastrnak, he could use a new left winger; Matt Beleskey was a solid contributor and successful signing on the whole but is better suited in a third-line grinding role than playing alongside Krejci against opponents’ top-six forwards.

Elsewhere, the Bruins should cut their losses and move on from acquisitions like Jimmy Hayes and Brett Connolly, two whiffs on the part of Sweeney’s staff. Those two players certainly do not fit the Bruins mold and seem to lack a crucial quality that the Bruins need to add to the team if they want to get back to the playoffs…

4. Add more character to the locker room

As easy as it is to point fingers at the coach for failing to get his team motivated for big games, there’s only so much Julien can do and he should not have to motivate his players for games like the Winter Classic. Some of the onus has to fall on the players.

No, the Bruins would not have been Stanley Cup contenders if they just had Chris Kelly on the roster all season. No, Shawn Thornton alone didn’t turn them from a President’s Trophy winner to a playoff pretender. But, looking at how this team has played down the stretch the past two seasons and the way they have responded poorly to big moments, I think it’s clear that the team lacks players of those guys’ character and locker-room presence.

Yes, Kelly is overpaid, but prepare for him to remain on the Bruins’ payroll because the team will probably bring him back; his impact off the ice and in the locker room has been invaluable. Players like Kelly, and Thornton when he was here, helped keep the team focused and confident heading into important games and big situations, and constantly held younger, less experienced guys accountable. Guys like Chara and Bergeron are not the “vocal” type of leaders; the team seems to be lacking that kind of voice.

Are guys like Kelly and Thornton hard to find? Are they worth overpaying? No, and no. But the bottom line is you need those character guys to have a winning team, a playoff team, and the Bruins haven’t had nearly enough of them in the past two seasons.

What do you think Don Sweeney should do to turn the Bruins around? Share your thoughts in the comments.

Matt Dolloff is a writer for CBSBostonSports.com. His opinions do not necessarily reflect that of CBS or 98.5 The Sports Hub. Have a news tip or comment for Matt? Follow him on Twitter @mattdolloff and email him at mdolloff@985thesportshub.com.