It has been a great summer for the Boston Celtics.

Last month, they surpassed the Los Angeles Lakers by claiming their NBA-record 18th title. On July 1, the Celtics agreed with Jayson Tatum on a five-year, $314 million extension, the richest contract in NBA history, and with Derrick White on a four-year, $126 million extension. On Sunday, they agreed to a four-year, $45 million extension with developmental success story Sam Hauser.

Boston will return all eight rotation players from last season's title team, with seven of those players under contract for at least the next two seasons and six under contract for at least the next three seasons.

And as currently constructed, the Celtics are headed toward another historic number: the league's first $500 million roster.

After inking Hauser to his extension, the Celtics have 11 players under contract for the 2025-26 season for a combined $225 million. If the roster is filled out with their own first-round pick and two players on minimum salaries -- projected to be each worth roughly $2.3 million, according to ESPN's Bobby Marks -- that would push Boston's payroll to about $233 million, more than $45 million over the projected luxury tax line.

Beginning next offseason, when much harsher penalties kick in for teams that are well into the luxury tax, the Celtics would be staring at a projected tax bill of $280 million, per ESPN's Bobby Marks, giving Boston roughly $513 million in combined salary and tax penalties for the 2025-26 season alone.

That number would shatter the current record of $388 million, set this past season by the Golden State Warriors, as well as the new projected record holders: the Phoenix Suns, who are on pace to break it in 2024-25 with a projected combined salary and luxury tax bill of $433 million.

No matter who winds up buying the Celtics over the next several months after longtime owner Wyc Grousbeck and his family put their controlling stake in the franchise up for sale, it's hard to see anyone being able, or willing, to afford those kinds of financial penalties for long.

For Celtics fans, basking in the glow of a championship and with a front office committed to retain its key players for years to come, it's likely frustrating to hear about the possibility of finances getting in the way of a potential dynasty. But this is also exactly what the league was hoping for in its negotiations for the current collective bargaining agreement.

"What I'm hearing from teams, even as the second apron is moving to kick in, the teams are realizing there are real teeth in those provisions," NBA commissioner Adam Silver said last week at his annual news conference at Las Vegas Summer League.

"I think this new system, while I don't want it to be boring, I want to put teams in a position, 30 teams, to better compete. I think we're on our way to doing that."

The new CBA was designed to help redistribute talent across the league and prevent teams from overloading their rosters with stars for a lengthy period of time. And while Boston's roster currently defies that logic, the massive tax bills heading the Celtics' way will eventually do the league's intended work.

For example: From the 2002-03 through 2021-22 seasons, the Celtics paid a total of $52 million in luxury taxes, per Marks. Over just the past two seasons, the Celtics have paid $114 million in taxes, and are set to pay another $66 million this coming season -- that's $180 million over a three-year span, before adding another $280 million for the 2025-26 season.

But while keeping this entire team together could prove to be a challenge -- if the Celtics win a second straight title in 2025, they'd certainly be inclined to try -- having so many players under contract also gives the franchise options.

With its entire starting five, Hauser and guard Payton Pritchard all on long-term contracts, the Celtics have the flexibility to go in a variety of different directions if they need to shed payroll. Despite the high tax bill and the restrictions on teams above the second apron, they will have the ability to reshape the roster from a position of strength.

As it stands now, the Celtics are currently projected to be close to $25 million over the second apron. Starting this season, teams who finish the season over the second apron will begin to have their future draft picks frozen (thus unable to be traded) as part of the penalties to prevent heavy spending over long periods of time.

But if the Celtics were to subtract just one of the big salaries from their books moving forward, and replace it either with draft picks or players on inexpensive, rookie-scale contracts, it would quickly become very plausible for Boston to get below the second apron, giving the Celtics flexibility to continue adding to the roster.

By comparison, the Suns are in a much different place. Bradley Beal is owed $160 million over the next three years and has a no-trade clause. The Suns' players on midrange salaries, Jusuf Nurkic, Grayson Allen, Royce O'Neale and Nassir Little, all have limited trade value, league sources told ESPN.

That leaves only Devin Booker and Kevin Durant, the team's two best players, and Josh Okogie, who was signed to a deal this summer designed to make him a trade chip over the next year, as the assets who could bring back value in a deal. And naturally, the Suns have shown no interest in trading Booker or Durant.

Boston certainly doesn't want to trade any of its players, either, and has gone out of its way to retain the continuity of its roster, with 13 of the 15 players from its title-winning team and both of its two-way players returning for next season. After winning 64 games, going 16-3 through the playoffs and winning the title in dominant fashion, the Celtics hope to replicate that formula again next spring.

But as the team continues to go through the sale process -- one that Grousbeck said would be wrapped up by "early 2025" -- the financial future of the team will hang over the franchise and will be among the first questions facing the new ownership group.

Multiple sources familiar with franchise valuations expect Grousbeck's stake to sell for roughly $5 billion, a record-setting price for the controlling stake of an NBA team.

For now, Boston's offseason business is virtually done. The roster is essentially set for next season, and with Hauser's extension on the books, its rotation is in place for the 2025-26 season, too. But as the Celtics prepare to open their title defense in the fall, they are fully aware of the half-billion-dollar fiscal cliff on the horizon and its impact on the franchise's pursuit of a dynasty.