The Paul Pierce era has finally reached its end in Boston.
So what happens now?
Well that answer is simple: Danny Ainge has to find Boston's next "Big Three" or "Fab Five" and surround them with a talented supporting cast.
It has been the Celtics' formula ever since Red Auerbach acquired Bob Cousy, Frank Ramsey, Bill Sharman, Bill Russell, K.C Jones and Tom Heinsohn to form a basketball dynasty—a dynasty that won a NBA championship the first year they were put together; a dynasty that went on to appear in 10 straight NBA Finals and won nine championships in total.
Ainge tried to follow that format when he was hired in 2003 and finally struck gold in 2007.
This offseason will make it more clear exactly who on the Celtics roster he wants to build around next.
We gathered from the selection of Kelly Olynyk in this year's NBA draft that he is one of those players.
Soon to be officially (re)acquired, MarShon Brooks is another person of interest.
He was the Celtics first-round draft pick in 2011, but was a draft night trade to the Nets for JaJuan Johnson (who was still on the board when Boston picked) and a 2014 second-round draft pick.
With Ray Allen and Avery Bradley on the roster, it was odd as to why the Celtics would add another shooting guard. Ainge may have had other plans in mind and was talked out of it.
This Paul Pierce to the Nets trade may have been brewing for longer than we know.
Speaking of Bradley, he and Jeff Green have shown signs that they can be stars in the NBA. An injury halted Jared Sullinger from fully showing what he is capable of, but he may end up being a star as well.
And Rajon Rondo is a mystery at the moment.
Then there is the matter of hiring a head coach to oversee this rebuilding project.
Today's Celtics are way different than the Celtic teams who struggled throughout the mid-to-late-'90s.
Back then, it was a period of lacking a solid core to build around and two bad coaching decisions (M.L. Carr and Rick Pitino).
A core was finally built with the 2001-02 Celtics team. You had three starters (Paul Pierce, Antoine Walker and Eric Williams) who had been drafted by the franchise in recent years. You had other solid players like Tony Battie, Walter McCarty and Kenny Anderson alongside them.
Not only did Boston return to the playoffs in 2002 for the first time in six seasons, but the team nearly advanced to the NBA Finals. They would return to the playoffs in 2003, where they once again lost to New Jersey, this time in the second round.
Despite finally getting back to their winning ways, it was newly hired general manager Ainge that decided to undergo a rebuilding process and build an entirely new roster. Thus, the team struggled again until the payoff in 2007-08.
Jim O'Brien, who had led the Celtics resurgence, resigned as head coach due to the decision.
The difference between what Ainge achieved in 2007 and what he is planning to do now seems to be a desire to build a team full of younger star players.
Let's face it: By 2007, Paul Pierce had been in the league for nearly 10 years. When things were finally going well earlier in his career, Ainge blew up the team.
Still, Pierce remained loyal. Every Celtic great had won an NBA championship—but him. Eventually, he would grow tired of rebuilding and want a better opportunity for that championship, either as a member of the Celtics or elsewhere, unfortunately.
So Ainge temporarily put aside the rebuilding for a quick fix. Kevin Garnett, Ray Allen, Sam Cassell and P.J Brown were a mix of NBA All-Stars and talented veterans nearing the end of their careers.
Eddie House and James Posey were young guys who were solid additions to the team. A win-win for everybody. Plus, the moves resulted in a immediate championship, but it was not designed to last.
Building a winning roster has worked for Boston numerous times in the past. So they will be a playoff team without Pierce, Garnett and perhaps Rondo faster than most think.
Advancing to the NBA Finals and winning more championships, on the other hand, will be where problems arise. That may be hard to come by when playing in the unpredictable Eastern Conference.
There will also be a period of early exits until they figure out the right mix of young players and veterans.
Fans of the Boston Celtics have been spoiled by winning. Danny Ainge was once a Celtic and he knows this very well.
Patience may not be on Ainge's side during this second rebuilding project.