Summer NBA power rankings are about as meaningful and accurate as preseason college football rankings. At least the NBA isn’t silly enough to have something like this matter in determining a champion. That would be stupid.

The top and the bottom of the poll are what you’d expect, but the Lakers and Celtics moved up while the Magic have fallen hard. You probably expected that, too. (Teams are listed with their record from last season.)

1. Heat (46-20) When you are the defending NBA champions you get to start on top (unless someone were to dismantle the team, Mr. Cuban). Miami got better this summer — and it is not just adding Ray Allen. More important is that the Heat have figured out who they are now and what they want to do. They have their identity. They are more dangerous.

2. Lakers (41-25) I think spots two and three — the Lakers and Thunder — are a toss-up. I could go either way and who is better may very well be decided in Game 7 of the Western Conference finals. But while there are questions about the Lakers — Steve Nash’s back, Dwight Howard’s back, Kobe Bryant’s knees, how all these stars mesh — on paper Howard and his defense are key and may make L.A. a little better than OKC. But they have to prove it now.

3. Thunder (47-19) While the Lakers have the potential, the Thunder are reality. We know OKC will come back a little better than they were last year, a little more experienced. And they already were very, very good. The Thunder have done this, they know how to do this, and they will be hungry. They are the bar the Lakers are shooting for, not the other way around.

4. Clippers (40-26) They will be better, because Blake Griffin will grow and improve, because Jamal Crawford is an upgrade over Mo Williams, and because I expect a bounce-back season from Lamar Odom. Besides, bad thumb or not Chris Paul is still the best pure point guard on the planet. But the level the Clippers reach in the playoffs will be determined by what kind of steps DeAndre Jordan makes.

5. Nuggets (38-28) I love the Andre Iguodala signing for them, I think he addresses their defensive needs on the perimeter and he fits what they do on offense. This is going to be a fun, fast team to watch. But the ultimate key will be the play of JaVale McGee for Denver and what George Karl can get out of him.

6. Celtics (39-27) Boston got better this summer — Jason Terry is an upgrade over Ray Allen, they will get Avery Bradley and Jeff Green back, and they figured out how well they play with Kevin Garnett at the five spot. It was a good offseason, Danny Ainge did himself proud. But they still need Miami to come back to them if Boston wants to make the finals. Also, they are not a regular season juggernaut.

7. Spurs (50-16) This is probably too low for them. We always tend to overlook the Spurs. Their stars will get a year older the question is can their young role players step up and help them out again? Probably.

8. Pacers (42-24) They should be better next season, mostly because they found their rotations and identity in the playoffs, with George Hill at the point. They could pass Boston for the No. 2 seed. Smart move to retain Roy Hibbert

9. Bulls (50-16) Derrick Rose is out for half the season (at least) and the Bulls have decimated their bench. And yet Tom Thibodeau will get them to defend like few others and that will win a lot of games. Regular season games. We’ll see come the playoffs.

10. Grizzlies (41-25) They lost O.J. Mayo but this is still a good team with real size up front (Marc Gasol and Zach Randolph). They still need shooters and someone to really organize the offense besides Mike Conley.

11. Knicks (36-30) Knicks fans will be convinced this is too low, that they should be up with Boston as teams to challenge Miami. I’m not sold. They should be a solid defensive team again (thank you Tyson Chandler) but I need to see Carmelo Anthony and Amare Stoudemire figure out how to co-exist on the court before I see New York getting out of the first round.

12. Nets (22-44) Well, they got a team they can take into Brooklyn. Who cares if they have a lot of large, long-term contracts they will hate in a few years (Joe Johnson, Brook Lopez). This team will be fun to watch and will put up points, but it’s going to take years off Avery Johnson’s life as he tries to get them to defend.

13. 76ers (35-31) Andrew Bynum gives the Sixers a new direction and I like the moves they made — if the East’s powers are going small (Miami, Boston) then counter by going big. Start Bynum and Spencer Hawes. I think they will be a good defensive team but the offense is going to be a work in progress.

14. Timberwolves (26-40) I think they are a playoff team in the West this year. Sure, the seven seed that gets the Lakers or Thunder in the first round, but it’s a start. I think they make a big move up, Kevin Love will be better and adding guys like Brandon Roy, Andrei Kirilenko and Chase Budinger gives Rick Adelman good depth to work with. They will miss Ricky Rubio for the first half of the season. How Roy plays could move them higher.

15. Jazz (36-30) This is a solid NBA team with good size up front — Al Jefferson, Derrick Favors and Paul Millsap. They will not be anybody’s pushovers, but in a deep West even good teams have to fight for a playoff spot.

16. Mavericks (36-29) They could make the playoffs if O.J. Mayo gets his groove back, Elton Brand stays healthy and productive, Chris Kaman has a career year… exactly. Well, they still have Dirk Nowitzki. And this is a placeholder roster as they keep cap space for next summer.

17. Hawks (40-26) Joe Johnson and the iso-Joe offense is gone to Brooklyn, but if that means more up-tempo offense, if it means more Jeff Teague/Josh Smith pick-and-roll it could be a good thing. I just don’t think they are as consistent, I think they are closer to a .500 side.

18. Bucks (31-35) The question isn’t will the Brandon Jennings/Monta Ellis backcourt score a lot, they will. And they will be entertaining. But who are they going to be able to stop? Defense is key in Milwaukee.

19. Warriors (23-43) On paper it’s a nice roster, but it needs Stephen Curry and Andrew Bogut to be healthy and productive like their old selves for it to work. I’m just not convinced they get that for the 70+ games they need from both of them.

20. Blazers (28-38) They have a couple quality young pieces — LaMarcus Aldridge and Nicolas Batum — and Damian Lillard is my guy for Rookie of the Year (Anthony Davis probably wins but he is too obvious). But it’s a rebuilding process and it will take some time.

21. Wizards (17-46) Where you rank them says what you think about John Wall and his ability to make the leap to elite point guard. Yes, they added Nene and Trevor Ariza and Emeka Okafor (all should help the defense), but this team is all about how Wall gets the offense going.

22. Raptors (23-43) They are a good dark-horse playoff team in the East, mostly because Kyle Lowry could help generate offense, and they have scorers like DeMar DeRozan and Andrea Bargnani. But what they really need is rookie Jonas Valanciunas to look a lot better than he did in the Olympics.

23. Pistons (25-41) I like their young core — Brandon Knight, Rodney Stuckey and Greg Monroe (who should have gotten a USA Select Team invite). And if rookie Andre Drummond comes along, they could finish up these rankings. There are reasons for hope.

24. Kings (22-44) They have an interesting frontcourt with DeMarcus Cousins and rookie Thomas Robinson. But this season in Sacramento is the “what do we really have with Tyreke Evans?” season. Well, that and when do the Maloofs do something else stupid.

25. Cavaliers (21-45) We all love Kyrie Irving. People outside of Cleveland are less sold on Dion Waiters and Tristan Thompson. And is this the year Anderson Varejao gets traded?

26. Magic (37-29) The post Dwight Howard rebuilding begins, but the roster having Arron Afflalo and Jameer Nelson may keep the Magic from sucking as much as the front office hopes (they want high draft picks).

27. Hornets (21-45) They have a young core to watch — Anthony Davis in the paint, Eric Gordon at the two, Ryan Anderson as a stretch four, Austin Rivers at the point — and Monty Williams will get them to play defense. It’s a rebuilding process, it’s going to take time. But they will be much better in March than they will be in November.

28. Rockets (34-32) They have Jeremy Lin and Kevin Martin. But I like what they did this summer even without getting Dwight Howard — don’t be middle of the pack, that’s just a rut you stay in. Be bad, get a high draft pick, and have trade flexibility. The Rockets have all that. They are ready for a good rebuild.

29. Suns (33-33) The post Steve Nash era rebuilding starts this year with the Suns being bad and getting a high draft pick. We’ll watch how Kendall Marshall pans out and we’ll watch Michael Beasley take a lot of shots. A lot of shots.

30. Bobcats (7-59) They are going to be better than last year. Thing is, they were the worst team in NBA history last year so even if they are better they could still be the worst team in the league.