And like that, on a dreary Friday morning in Boston, the final curtain fell on the Big 3 era.

Yes, Avery Bradley was more of an epilogue, as that era truly ended with the Nets’ draft-pick bonanza more than four years ago, but when Danny Ainge sent Avery Bradley, one of the top three draft picks he’s ever made, it removed the last guy to suit up in green alongside Paul Pierce, Kevin Garnett and Ray Allen.

Bradley, who was dealt along with a second-round pick to the Detroit Pistons for Marcus Morris in a trade first reported by The Vertical, played seven seasons in Boston, earning a pair of All-Defensive team nods and improving his game to near-All-Star status.

Bradley averaged career-highs of 16 points and six rebounds last year, knocking down 39 percent of his 3-pointers and playing his usual high-caliber defense. He’s one of the league’s best one-on-one defenders, and while he’s not as good with help defense, was always a guy who gave the Warriors fits.

Let’s break the trade down.

Why make the deal?

Unless they went back to Gordon Hayward and asked him to take slightly less than max money, the Celtics had to trade one of three guys: Bradley, Marcus Smart or Jae Crowder. It would be interesting to know what the league’s interest in Smart was, but most of the rumored deals centered on Bradley, the best player of the bunch, and Crowder, who is on the best contract.

Bradley is an unrestricted free agent next offseason and will demand a sizeable contract, likely north of $20 million a year. If that sounds crazy, Tim Hardaway Jr., a shooting guard who is one year younger and not as good at basketball as Bradley, just got a four-year offer sheet worth about $18 million per season. If the Celtics had re-signed Bradley and Isaiah Thomas, in addition to Horford and Hayward’s deals, they would have had little payroll flexibility moving forward.

With this move the Celtics saved nearly $4 million against the cap, which will allow them to keep Terry Rozier and possibly bring Guerschon Yabusele, a bruising power forward, over from Europe.

How good is Morris?

To borrow a common phrase from my dining reviews, he’s good but not great. The 14th pick of the 2011 draft -- one spot ahead of Kawhi Leonard and 11 guys before Ainge took MarShon Brooks -- is a 27-year-old 6-foot-9 combo forward (Bradley is 26 and 6-foot-2) who basically averaged 14 points and five rebounds the last two seasons as a regular starter for the Pistons (he went for 18 points and three rebounds a game in his lone playoff series in 2016).

While he played about 95 percent of his minutes as a small forward last year, as recently as 2014-15 he was splitting 69 percent of his minutes between power forward and center. He can defend three positions, has decent quickness without a ton of lateral speed and while he’s not a great passer, he’s not prone to turning the ball over.

The question will be how good of an outside shooter is he. He hit just 33 percent from deep last season, and shot 34.5 percent combined the past two seasons, which is just about league average. His 50.8 true shooting percentage in 2016-17 was 10th worst among both small forwards and power forwards. He did hit 43.6 percent of his corner 3s, which used to be Kelly Olynyk’s specialty in Boston.

While the numbers may be skewed a bit by how much small forward he played for Stan Van Gundy, he is more comfortable shooting from outside than pounding down low. More than 60 percent of his shots came more than 16 feet from the rim last season, with less than 20 percent coming inside 10 feet.

He’s a guy who was twice traded for a second-round pick, but has blossomed into a legit starter in Detroit once he got regular minutes. He put up 9.3 combined win shares over the last two seasons, with a combined PER of 25.1. Meanwhile, Bradley was worth 7.9 win shares, which probably doesn’t credit his defense enough, and put up a combined 27.6 PER over the past two seasons.

What about the second rounder?

Don’t worry about it. It’s the Celtics’ own pick in 2019, so it should be safely in the 50s. The Celtics have more picks than they can reasonably make over the next couple of drafts, so sending this one away is a non-issue.

What about Morris’ contract?

It’s a bargain. He has two years and about $10.4 million left on a four-year, $20 million below-market deal he signed with Phoenix in 2014, when the Suns were promising they would keep him and twin brother Markieff together. That didn’t work out, and now there’s a considerable chance he faces Markieff and the Wizards in the playoffs.

What’s the lineup look like now?

There’s a decent chance Ainge is finished with major roster construction. He’s probably still a little salty the Pacers didn’t have the patience to wait for Hayward’s decision, in which case Boston might have re-offered its “two starters and three non-lottery draft picks for Paul George” offer that was widely reported. There’s still likely a big man signing using the mid-level exception and maybe a veterans’ minimum deal or two, similar to what Gerald Green got last offseason.

But for now, the Celtics appear prepared to enter the season with a starting lineup of Thomas-Hayward-Crowder-Morris-Horford and a bench of Rozier, Smart, Jaylen Brown, Jayson Tatum and Ante Zizic. Throw in second-round pick Semi Ojeleye, Yabusele and maybe a guy like Abdel Nader, a 2016 second-rounder who has looked good in summer league, and that’s most of your roster.

It’s almost like the Celtics have two teams rolled into one: their Win in 2018 squad, which is the starting lineup and has been acquired entirely through trades and free agency, and their Win in 2022 squad, which is the second five and features most of Ainge’s recent draft picks.

So while he turned the corner from one franchise era, Celtics Nation may be on the precipice of two more.

Follow Brendan Kurie on Twitter @BrendanKurieSCT