FILE – In this Oct. 30, 2018, file photo, Boston Celtics center Al Horford (42) dunks the ball against the Detroit Pistons during the first half of an NBA basketball game, in Boston. A person familiar with the decision says Celtics center Al Horford will forgo his player option for next season and become an unrestricted free agent. The source spoke on the condition of anonymity Tuesday, June 18, 2019, because the decision has not been announced. ESPN was first to report Horford’s decision. (AP Photo/Mary Schwalm, File)

Now on the clock: Chaos.

The NBA offseason is about to kick into high gear.

A draft that had good bits of intrigue — at least after New Orleans’ Zion Williamson, Memphis’ Ja Morant and New York’s R.J. Barrett were chosen first, second and third in moves that were widely expected for weeks — is now done. Up next is free agency, which will be much more unpredictable when it begins on June 30.

Kawhi Leonard, Kevin Durant, Kemba Walker and Kyrie Irving all were All-Star starters this past season and may soon change addresses. So might fellow All-Stars Khris Middleton, Nikola Vucevic and Klay Thompson. Al Horford has apparently decided to leave Boston. Anthony Davis has already been traded to the Los Angeles Lakers, or at least will be traded when the new league year begins July 6.

“We’ll have more answers then,” Boston Celtics President Danny Ainge said.

In the meantime, questions abound.

The Celtics are bracing to lose both Irving and Horford; Irving led Boston in points and assists per game, Horford led the team in rebounds per game. Ainge, when meeting with reporters after the draft, wasn’t willing to say much about either situation since nothing is technically done yet — but his message was clear nonetheless.

“Listen, I’ve always said that when somebody goes, then somebody else gets a new opportunity and we’ve seen that happen here many times,” Ainge said. “And I’m very excited about what the possibilities are over the next month. … Maybe the players and the names on the jerseys change, but the approach is the same. We have a very attractive franchise to play for.”

More than 200 players are free agents. The available salary cap space around the league for next season alone exceeds $500 million. Add up the value of every deal that’s going to be signed starting on July 6, and it’s conceivable that teams will combine to commit more than $2 billion in new salaries over the next four or five years.

“I feel like I’m going to need every dollar,” Philadelphia 76ers general manager Elton Brand said.

He’s not alone. It is going to be a spending frenzy.

Luxury real estate agents in the few York area might be drooling at the thought of the Brooklyn Nets and New York Knicks having well over $100 million in cap space to play with this summer. That sort of available cash means both the Nets and Knicks could conceivably lure two max-salary players to their clubs, and both franchises are certain to pursue the big names like Leonard, Durant, Walker and Irving.

“I don’t know what they’re going to be interested in, but when they look at Brooklyn from afar we’ve got to give them some credit because the guys that are free agents, all of them have spent the last year or two surveying the league,” Brooklyn Nets general manager Sean Marks told reporters early Friday. “They know where they want to go and what they want to be a part of.”

Walker could command $221 million from Charlotte, though he has said he will take less. Durant could get the same from Golden State, and he hasn’t said he would take less. Leonard is probably the biggest mystery case that needs solving; the now two-time NBA Finals MVP could end up with the Los Angeles Clippers, he could stay with the NBA champion Toronto Raptors, or look to New York. And as is almost always the case with Leonard, there have been no real hints.

Some oddsmakers in Las Vegas already say the Lakers — with Davis teaming alongside LeBron James and potentially a third star player — are the favorites to win the 2020 NBA title. Those odds could swing big-time in the next few weeks.

“If you’re asking now, with the way the Western Conference looks or the league looks in general, I couldn’t even venture a guess kind of how that stacks up because we’re so far from the off-season really ending,” Oklahoma City general manager Sam Presti said. “Every team is going to do what they can to come back better.”

It was already going to be a wild summer, and the decisions that are looming got even more interesting — unfortunately so — when Durant and Thompson endured major injuries during Golden State’s loss to the Raptors in the NBA Finals. Durant tore an Achilles, Thompson tore an ACL.

Both will miss, at minimum, most of next season. Still, the Warriors clearly want to retain them.

“Those are guys that you do everything you can to keep within your organization,” Warriors general manager Bob Myers said, when asked about the looming pursuit of Thompson and Durant.

Free agency isn’t the only mechanism that will be in play over the coming weeks.

Some teams, if inclined to dramatically change the makeup of their rosters, will have to do so through trades this summer. Miami, a team never shy about getting into the free-agent fight, isn’t likely to be that active this time around because it lacks cap space.

“There are possibilities,” Heat President Pat Riley said.

“Possibilities” will be a buzzword in the NBA for the next few days, until the circus begins at 6 p.m. Eastern time on June 30.