You don’t need me to tell you how much is at stake tonight, and potentially in Game 7 on Thursday, for everyone involved in this series. The NBA Finals is as big as the sport gets every year, but especially so when the series involves so many of the game’s most transcendent and polarizing figures.

If the Heat lose this series — and that’s a big “if” with the two remaining games in the land of DOS MINUTOS, this scary lady, the hilariously awful “Seven Nation Army” chant, and white T-shirts masquerading as seats for the game’s first six minutes — the most interesting question coming in the series is whether the Heat will reinvent their defense going forward. Since signing LeBron James and Chris Bosh, Miami has adopted the ultra-aggressive, helter-skelter defense we all know so well by now — swarming traps on the pick-and-roll, sometimes all the way out to near half court, with terrifying outside-in rotations behind the play. That defense is demanding. It requires the two players on the ball — the man guarding the ball handler and the big man guarding the screener — to blitz out hard on every pick-and-roll, on every possession. It requires the wing players defending shooters along the 3-point arc to crash far into the paint, bump the big man rolling to the rim, and, once that’s done, to dart back out and prevent a catch-and-shoot 3-pointer.

That strategy has largely worked. The Heat have been ranked fifth, fourth, and seventh, respectively, in points allowed per possession over the past three seasons. They’ve managed fine against most of their playoff opponents. And their style fits the Heat’s personnel — both its strengths and weaknesses. It leverages the insane athleticism of the Heat’s foundational stars; Chris Bosh is probably the fastest center in the league, and LeBron James and Dwyane Wade, when healthy, are unmatched in their ability to protect the basket with highlight shot blocks and retreat out to long-range shooters. (They are also unmatched in their ability, it seems, to cost their team points in the FREAKING NBA FINALS by whining to officials as play continues behind them.)

But the Heat have also shown signs of breakage and fatigue in all three of those postseasons. The 2011 Mavericks and 2013 Spurs, elite passing teams sporting tentpole superstars and a heavy emphasis on 3-point shooting, have torn up that high-flying defense in two championship series — at least so far in the case of these Finals. Those teams deserve most of the credit for all that scoring. The best way to beat the Heat’s trapping and scrambling, a scheme that by its nature places two men on the ball and thus creates a 4-on-3 elsewhere on the floor, is to pass the Heat to death before launching an open 3-point shot.

But the Heat’s issues on defense in the playoffs, when they’ve cropped up, have gone beyond the brilliance of elite opponents. They’ve made an alarming number of basic mental errors in this series — losing track of San Antonio shooters on simple cuts, miscommunicating on switches, failing to retreat in transition, inattentive ball watching, poor positioning, etc. The transition issues popped up against the Pacers, who scored at nearly a top-10 rate against Miami, even with a bundle of embarrassing Pacer-esque turnovers.

And the Heat’s defense in the conference finals against Boston last season was a complete mess through five games. The Celtics, one of the league’s very worst offensive teams that season (and for the last four seasons), absolutely tore Miami apart in taking a 3-2 lead. It was one of the most surprising short-term playoff trends in recent memory, and the Celtics took advantage of the same litany of mistakes the Spurs have feasted upon in this series.

The Heat were missing Bosh for the first four of those Celtics games, and for most of the fifth one, and his play during most of these Finals has been a reminder of how impactful he can be defensively when he’s healthy. But Bosh’s absence should not have resulted in a maddening drop in basic defensive basketball IQ among his teammates.

They beat the Thunder in last season’s Finals mostly behind a scoring avalanche for which Oklahoma City’s young defense had no answer; the Thunder scored at a top-five rate in that series, though “top five” for that team was a slight step down.

Bottom line: I wonder if Miami’s defensive scheme has inherent limits, in terms of specific opposition and the Heat’s own mental and physical exhaustion. If I ever get a chance to sit down with Erik Spoelstra in the offseason, over a beer or two, I’m starting the conversation here. We are compiling evidence that a certain type of offense, with loads of time to game-plan for only the Heat, can hurt Miami. And the rest of it — the puzzling breakdowns in the half court and transition — is the mark of a tired, addled team.

Again, that’s not a knock on the system itself. It fits the personnel, especially since the Heat have not been able to find a rim-protecting big man who can defend on the block and stay on the floor for heavy minutes — a tough commodity when you’re working with the veteran’s minimum. And there just aren’t a lot of minutes for that sort of player if the Heat are committed to playing with only one traditional big on the floor — a setup that won them the title last season. Changing the system also involves changing the personnel. It will be an interesting offseason in Miami, win or lose.

The Spurs’ defense provides a useful contrast — as do defenses in Chicago, Indiana, and Memphis. These teams all feature more traditional big men, and for the most part, they do not blitz on pick-and-rolls. The Spurs like to have their big men — Tim Duncan and Tiago Splitter — drop back toward the foul line, protecting the paint and conceding, to at least some degree, lower-value midrange shots. It’s an imperfect strategy, one San Antonio had to adjust against the flammable Stephen Curry by having Duncan and Splitter take a very important extra few steps out toward the 3-point arc.

The goal is to have the two men directly guarding the pick-and-roll — Duncan and Parker, for instance — do most of the legwork in bottling it up, so that the three other defenders guarding shooters can stick close to home.

And it has worked just well enough in this series to redistribute some of Miami’s shot attempts from high-value areas, and high-value play types, to low-value ones.

To wit, nearly 20 percent of Miami’s possessions in this series have ended with a pick-and-roll ball handler either shooting, drawing a foul, or turning the ball over. Only 13.6 percent of Miami’s possessions in the regular season ended in that fashion, and the 20 percent mark they’ve put up in the Finals would have been the largest such share among all 30 teams — by a long shot, per Synergy Sports.

That sounds good, right? You run a pick-and-roll with Wade or James, and one of those guys ends the possession by shooting. Those guys are stars!

But that’s actually not good. The league’s very best defenses enjoy when pick-and-roll handlers take a lot of shots, because those defenses know they can keep those shot attempts away from the rim and in the dreaded midrange area. And if those pick-and-roll ball handlers are shooting a lot, they’re not doing something else: getting into the lane and passing out to open 3-point shooters for the game’s most delicious spot-up looks. That’s when the Heat are really rolling — when the pick-and-roll is both a vehicle for LeBron and Wade to score, and a vehicle for those guys to hit the army of open shooters around them.

In the regular season, about 38 percent of Miami’s shot attempts came on long 2-point jumpers or those tricky floater shots that come in the paint but outside the restricted area, per NBA.com. That combined share is up to 45 percent in this series, with a corresponding decline in better shots — corner 3-pointers, shots at the rim, and 3s from non-corner areas. That difference amounts to only a few shots per game, but in a short series between the very best teams, swinging a half-dozen shot attempts this way can mean everything.

About 25 percent of Miami’s shots in the regular season were spot-up jumpers, and they scored 1.1 points per possession on those plays, the best mark in the league, per Synergy. They scored “only” 0.824 points per possession when their pick-and-roll ball handlers finished plays, and that was the seventh-best mark in the league. But in this series, only 21.5 percent of their possessions have finished with spot-up jumpers, per Synergy.

There’s no magic to how the Spurs are doing this. They’re clogging the lane, staying home on the Heat’s most dangerous 3-point shooters, and helping off the weaker ones:

It’s all here: Wade and Bosh have run a very low pick-and-roll near the foul line. Kawhi Leonard is trailing Wade closely, and Splitter has used his speed to bottle up Wade without losing track of Bosh behind him.

And look at the help: Diaw is ready to pounce off of the cold Shane Battier, and Touched by God is on Mario Chalmers in the right corner. Manu Ginobili, meanwhile, is sticking right next to Ray Allen, even though most typical pick-and-roll schemes would require him to help here. The play results in a very tough Wade floater from outside the restricted area. On a side note, Chalmers is the one guy who would scare me a bit if I were the Spurs. He has a quick release, he’s a good shooter, and the Heat would be wise to kick him the ball on plays like this. But as we’ll get to later, it’s unclear how the Heat will divvy up minutes tonight.

Here’s another Wade pick-and-roll, with the Spurs clogging the lane:

Again, nothing fancy. The Spurs help off the right guys, and both Green and Leonard have been fantastic at doing that and then scampering back out on shooters before they can actually shoot.

The Spurs are also not fouling, which is absolutely giant against Miami, and has long been one of the team’s, and especially Duncan’s, very best skills. LeBron has drawn exactly zero shooting fouls in this series out of the pick-and-roll, per Synergy; he drew shooting fouls on nearly 15 percent of his pick-and-roll finishes in the regular season. Wade’s foul-drawing rate has dropped by nearly half, and the Heat as a whole have earned just one foul shot for every five field goal attempts in this series — a number that would have ranked 29th, just ahead of the pathetic Magic, for the season. That’s very bad news for a team that has been among the top 10 in that category since this group of stars joined up.

Another thing: James has taken only 10 total shots out of the pick-and-roll in this series, about one per game fewer than his season average. And that understates the decline, since he’s also not drawing shooting fouls. He just hasn’t been able to get comfortable attacking the rim this way against San Antonio.

Know who has? Wade. Flash has jacked 7.2 shots per game via the pick-and-roll, nearly twice his season average, and though he’s shot a tidy 20-of-36 on those plays, his production on them has been volatile game-to-game. And if he’s not getting to the foul line, the Spurs will accept the trade-off of giving Wade tough floaters if doing so means preventing Miami’s shooters from going off.

When James can’t score or create 3-pointers out of the pick-and-roll, he and the Heat usually compensate via post-ups. Those have failed badly in this series. The Heat have shot just 11-of-35 via post-up chances in the Finals, and they’ve scored a piddling .615 points per possession on those plays in this series, per Synergy Sports. That number would have ranked dead last in the regular season, by a giant margin. The Heat ranked first overall in that category during the regular season, so this is a catastrophic decline. Leonard and Diaw have been sensational defending LeBron on the block, and the Spurs have done well with targeted help. The Heat and LeBron need to figure this out tonight.

And Wade’s post game has fallen apart without his usual explosion. He’s 6-of-25 on post-up shots in the playoffs, and he has drawn zero fouls on those plays. In Game 5, the Heat called one post-up for him out of a timeout, and after spinning by Ginobili — who should be overmatched against Wade on the block — Wade saw Duncan coming to help, and, rather than going at or around him, launched a tough baseline floater that had very little chance of going in.

It all adds up to this: Miami has had huge problems scoring after San Antonio field goals, when the Spurs can set up their defense. The Heat have scored just 0.9 points per possession in such situations, far below the league’s average, according to an internal parsing of play-by-play data completed by an NBA team not in the Finals. They’ve scored at a blistering rate off Spurs misses, according to that analysis.

Tonight, the Heat have some interesting lineup decisions to make with their season on the line. They’ve been better on both ends in this series with Mike Miller on the floor, but he has struggled on defense and somehow attempted just two shots combined in the last two games. That’s in part because the Spurs are sticking more closely to him than they are to Battier, Chalmers, and Norris Cole.

Battier has been much cleaner on defense than Miller. He’s bigger and stronger, more versatile, and he hasn’t had the same blatantly bad bouts of miscommunication and confusion. Spoelstra and his staff have surely thought about starting Battier for Miller tonight, and returning to the sorts of small lineups that won them last season’s title. That would cramp the Heat’s spacing at first; the Spurs are getting braver and braver in ignoring Battier to clog the paint, and if Battier doesn’t make them pay early with an open 3-pointer or two, they’ll just keep on doing that until Spoelstra removes him.

And speaking of spacing, the Heat have scored 116.2 points per 100 possessions in 132 minutes with Allen on the floor in this series, and just 93.5 in 108 minutes without him, per NBA.com. Even in a small sample, that is an eye-popping gap any team would have to take into account; it’s much larger than the difference between Miami’s league-best offense and Washington’s league-worst brick machine. The Spurs are having some trouble chasing Allen around screens, and the Heat should use more of that action tonight, both to spring Ray and to draw attention to him as a decoy. Allen is quietly having a very good series, at least on offense.

The Battier-Allen-Miller conundrums coalesce around one related question: What about those small lineups that include two of those three, and thus neither of the Chalmers-Cole point guard combo? Only two such lineups have played at least five minutes in this series, but those two groups are plus-nine combined in 18 minutes and showed promise at the end of an otherwise disastrous Game 5. Spoelstra showed in the Indiana series that such late-game production from a seldom-used group at the end of a loss — Game 6 in that case — can affect his rotation in the next game.

The downside of those lineups, of course, is that LeBron has to spend lots of time guarding Parker. Want to get really tired? Guard that little French guy for 35 minutes. I get tired just watching it. The Spurs have won that matchup in the very limited time it has existed, mostly by confusing James with various fast-moving pick-and-rolls. And in Game 5, when those lineups played a ton for the first time in the series, the Heat punted on the LeBron-Parker matchup by switching when the Spurs had another wing or guard screen for Parker.

Breaking news to zero people: Parker can blow by Miller, Battier, Allen, and Wade on switches.

There’s also the lingering Birdman question. Chris Andersen hasn’t played in two games, and he played just seven minutes combined with Bosh over the first three games of this series. If the Heat are going small for the full 48, there just isn’t room for both Udonis Haslem and Andersen in the rotation. That’s really all that is going on here. They’ll only go to Andersen if Haslem struggles, and I’d expect them to do so if Haslem poops the bed again tonight. The Spurs, as you can see in that second photo above, aren’t paying all that much attention to Haslem when he stands along the baseline. They won’t pay attention to Andersen, either, but Bird can at least hurt them by catching and dunking from there.

But he can’t guard Duncan in the post, just as he couldn’t guard Roy Hibbert. He’s just not strong enough. Haslem has done well fronting Duncan and being physical with him, and Andersen isn’t as good at either tactic. But he should have no trouble staying on the floor when Duncan sits.

And the Spurs? They’ve got zero rotation questions to answer. They’ve built a roster that can play big and small, and with the reanimation of the Argentine Savant, the smaller lineups that struggled for most of this season worked again on Sunday. If that holds for one more game, San Antonio will likely be holding the trophy tonight.