The NBA has the worst regular season. It’s not even close. Think back: When last did you see an NBA game before the Ides of April that you could recall a week later? The league plays 82 games over six months to eliminate 46.7 percent of its teams, meaning there’s no such thing as a playoff race in pro basketball. (The more heated competition is to land in the lottery.) No wonder the best players are more concerned with “load management” – sports-speak for “sitting this one out” – than anything that happens in Games 1 through 82.

The NBA also has the best offseason. That’s not close, either. Almost no big-name NFL players become free agents. Baseball has its big-ticket free agents, but Bryce Harper and Manny Machado needed four months to find new homes; Dallas Keuchel and Craig Kimbrel needed until June. By way of contrast, Kevin Durant and Kyrie Irving needed a couple of minutes.

No other league can reconfigure itself in the span of a few days. The NBA does it periodically. There are no Mike Trout lifetime deals in hoops. NBA players were smart enough to ensure that the biggest names would always have leverage. LeBron James has changed teams three times since 2010. Durant is on his third team in four seasons, though it’s doubtful he’ll play for his new club until October 2020. Irving is on his third in four. Al Horford will be on his third in five. Jimmy Butler is angling to make it four in four.

The way the NBA works is this: If a big name wants to leave, he’ll have his chance; if he’s among the biggest of the big, his leaving can rearrange the landscape. As much heat, pun intended, as LeBron felt after “The Decision,” his talents-taking to South Beach marked a new paradigm. He and his Super Friends took the Heat to four consecutive NBA finals. Then he returned to Cleveland, where he did the same. Now he’s a Laker. Year 1 went horribly. In Year 2, he’ll be paired with Anthony Davis.

A month ago, you’d have figured Golden State’s string of finals appearances was in no immediate peril. Today the dominant team of the past five years is, with Durant gone and Klay Thompson recovering from a torn ACL and the invaluable Andre Iguodala apparently outbound in a sign-and-trade for D’Angelo Russell, in major flux. Indeed, today it would be hard to name the NBA West’s best team.

Is it LeBron’s Lakers, who have two superstars but not much else? Houston, which couldn’t get past Golden State but might now have no need? Denver, which finished second in the West and just re-upped Paul Millsap and Jamal Murray? Portland, which retained Damon Lillard and Rodney Hood? Utah, which added Mike Conley, Bojan Bogdanovich and Ed Davis?

Or could it be the Clippers, who’ve never won anything ever but who are making a pitch to Kawhi Leonard, who stamped himself as LeBron’s heir apparent by taking Toronto to the title? Some eventful NBA offseasons only see the rich only get richer, as happened when Durant aligned himself with the Warriors. A summer like this is without precedent. The Clippers could become a huge deal. The Eastern Conference’s longstanding version of the Clippers already did.

The East likewise hangs on Leonard. If he stays with the Raptors, they’ll be favored to repeat. If he doesn’t, Milwaukee assumes the mantle, though the Bucks just lost Malcolm Brogdon, maybe their second-best player, to Indiana. Horford is leaving Boston for Philadelphia, where he finally gets to play power forward, the 76ers already having Joel Embiid.

Having lost Horford and Irving, the Celtics will try to compensate with Kemba Walker, whose departure from Charlotte could make the Hawks, who haven’t yet joined the free-agent fun, no worse than the second choice behind Orlando, which kept Nikola Vucevic, in the NBA Southeast. (This depends on what you think of Butler, who could land in Miami.)

The big NBA noise, for the first time ever, involves the Nets, who were last really good when Julius Erving was performing with the red, white and blue ball in the old ABA. Brooklyn – yes, Brooklyn – now has two franchise players in Durant and Irving. (Not to be confused with Erving.) Trouble is, Durant is apt to play his first game as a Net at 32, and he and Irving are both finishers, as opposed to distributors. As we know, Irving bristled at playing alongside LeBron, who’s both finisher and distributor. Is one franchise big enough for him and KD?

We once thought that only those Summers of LeBron could yield such seismic impact. LeBron, however, had little to do with this. He’s still a Laker, and there’s a question as to whether, at 34, he’s still LeBron. What we saw over the weekend, what we await as Leonard makes his choice, could be the dawning of a post-LeBron, post-Warriors NBA. For the better part of a decade, the sport has essentially been one or the other. There’s a real chance it’s now none of the above.

We say again: Nobody does offseasons like the NBA. One day in, this one has been astonishing. This summer has been so stunning it might make you want to watch an actual NBA game before next spring.