I could easily see Bergeron saying run it back one more time because of the regular season promise and because the playoffs ended as they did.
Easier said than done if all this is true (I didn’t write or research it):
The Bruins really went on a spending frenzy what might be Bergeron's last season. This offseason, the bill is due.
They're walking into the season with 4.5 million in cap penalties from performance bonus overages
Pastrnak and Zacha's extensions kick in, increasing their cap hit by 5.83 million
They have 14 contracts active, and about 6 million in cap space (10.5 mill - 4.5 mill penalties) to work with. They can't even get to a roster of 23 players with 9 league min contracts, and that's assuming all their RFAs/UFAs who want to make above 750k leave.
They obviously will want to keep a few UFA/RFAs who will demand more than 750k, so someone has to leave. Most of their big earners have some sort of NTC or NMC. Debrusk, Zacha, McAvoy, Carlo, and Grzelcyk are the players that can be traded with no restrictions.
Orlov and Bertuzzi cannot no longer be afforded with the salary retention running out
The hardest thing is goaltending. Swayman is a arbitration eligible RFA. Statistically, Swayman was a top-4 goaltender this season, and a lot of teams would love to lock up a player like that with an offer sheet (the Devils are a great example). Arbitration is difficult since players like this are so rare, but if Jack Campbell got 5x5, I can't imagine Swayman would get less. Boston can't afford to pay that - they could probably offer a 2 year cheap bridge deal (depending on who they trade away from the above list). Therefore, Swayman staying would likely require him to be willing to give up 20 million or more in guaranteed money. It's really hard to spend more on goaltending with the penalties and extensions. At that point, the temptation might be to trade Ullmark, but he has a NMC, so it might be hard if he doesn't want to move.
Trent Frederic is arbitration eligible. Using other forwards as a benchmark, he's likely due 1.5 - 3 million, depending on contract term (longer=more money). I would guess shorter term, lower side of that range, but still a bit more than league min.
They have 1 pick in the top 64 in the next 3 drafts, and their prospect pool has been rated as one of the worst in the league.
There is going to be some hard decisions coming before the start of the next season.