The Eastern Conference finals are a battle between two teams that took very different paths to get to the same spot.

The No. 2-seeded Boston Celtics cruised through the regular season, finishing a game shy of the best record in the NBA. But they’ve struggled a bit in the playoffs, taking six games to dispatch the Atlanta Hawks in the opening round before having to come back from a 3-2 deficit in Round 2 to beat Joel Embiid, James Harden and the Philadelphia 76ers (who have since fired coach Doc Rivers).

The eighth-seeded Miami Heat struggled in the regular season and trailed with less than five minutes to go in a must-win play-in game against the Chicago Bulls. But they righted the ship, coming back to beat the Bulls before stunning the top-seeded Milwaukee Bucks (who have since fired coach Mike Budenholzer) in five games in the opening round. They then beat the New York Knicks convincingly in six games in Round 2.

But both teams are four wins away from the NBA Finals, a place each has been in the last five years. The winner will face either LeBron James and the Los Angeles Lakers or Nikola Jokić and the Denver Nuggets (on ESPN) with the title on the line.

And there are some key matchups that will factor into who will emerge from this rematch of last season’s ECF. Here are five of the biggest questions heading into this Heat vs. Celtics series.

1. Who Is the Alpha in This Series?

Once upon a time, Jimmy Butler was a part of the much-maligned “Three Alphas” in Chicago with the Bulls.

But for the Heat to win this series, Butler is going to have to be the alpha all by himself. If he isn’t the best player in the series for coach Erik Spoelstra, it will be hard for the Heat to pull off the upset.

He certainly can be, of course. He’s on the short list of players who have performed the best this postseason. Among players who have played 10 or more games in the playoffs, Butler is second in points per game with 31.1.

In a series against arguably the best player in the world, Butler was the one who made the difference in the opening round against the Bucks. And in the second round, Butler wasn’t as flashy and missed a game, but still looked like the best overall player against the Knicks.

The Heat offense will only stave off the smothering Celtics defense if Butler is the catalyst. He has to score a bunch of points efficiently and make good decisions.

Boston will throw several good wing defenders at Butler, as Jaylen Brown, Marcus Smart and Jayson Tatum will all get their shots at slowing him down. But when Butler gets a switch to a player that isn’t as suited to guard him, he has to make the Celtics pay.

Whether it’s a big man like Al Horford or a smaller player like Derrick White, Butler has to exploit those mismatches to get the stingy Celtics defense to bend. To his credit, very few players sniff out exploitable matchups as well as Butler. As soon as White switched onto him this year, he went without hesitation.

These are the immediate decisions Butler must make to impose his will on the series.

Fortunately for the Celtics, they have a player who can go shot for shot with Butler when he’s at the top of his game in Tatum. Coming off a 51-point performance in Game 7 against the Sixers, Tatum heads into this series looking to assert himself once more. And the Heat haven’t had an answer for him in the four matchups this year.

Tatum averaged 30.8 points and 10.5 rebounds on 47%/39%/85% shooting splits. Butler wasn’t there for two games, but it didn’t seem to matter. Tatum took advantage of several semi-transition opportunities, making the Heat pay for not getting a body on him early enough in the possession.

Miami allows a ton of 3-pointers (more on this later), but this one is unacceptable. Letting the Celtics’ best player walk into an open 3 at the top of the key is a sure way to get burned. The Heat have to force Tatum into tough reads and tough matchups.

Jaylen Brown deserves a mention here as well, as he’s been arguably even better than Tatum against the Heat this year. Brown averaged 30.3 points on 58%/40%/88% splits in three games. The Heat can’t afford for either Tatum or Brown to continue this type of onslaught. If they both do, Miami is doomed.

If Tatum (or Brown) can outplay Butler, the Heat will need everything else to go their way to hang in the series. If Butler continues to be the best player on the floor, the Heat will have a chance, as they’ve shown all postseason.

2. Can the Heat Win the Possession Game?

Boston’s regular-season statistical resume is impressive, but one weak spot is the lack of forced turnovers. The Celtics forced the fifth-lowest turnover rate in the league this season.

This wasn’t a big deal, as the disciplined Celtics defense still ranked first in our adjusted defensive ratings. But Miami can use this to its advantage.

The Heat were 13th in offensive turnover rate during the regular season but have been in the top five in terms of lowest turnover rate in the playoffs.

Butler has long been an analytics darling (he was 24th in our DRIP metric among those with at least 1,000 minutes during the regular season) due in part to his propensity to take care of the ball. He had just eight turnovers in five games against the Knicks. With the Heat running even more of the offense through him in the playoffs, they have done a good job of taking care of the ball.

Boston has taken care of the ball as well these playoffs, but Miami is better at turning the ball over on defense. Miami forced the third-most turnovers in the league this season.

The Celtics get a better shot profile than the Heat and were significantly better offensively throughout the year. The easiest way for the Heat to neutralize that advantage is by getting more possessions.

If the Heat continue to be turnover averse and force the Celtics into some, it’ll put them on more even ground.

3. Can Miami Cut off the Corner?

The most glaring weakness for the Miami defense is one Boston is equipped to exploit.

Miami allowed the most corner 3s per game this season, and opponents shot 39.8% on those 3s. Boston took the most corner 3s of any team in the league this season and hit them at a 40.4% clip.

You might think Miami’s tightened this up during their playoff run, but the team has allowed the most corner 3-point attempts per game in the postseason as well. So this is an obvious pressure point for Boston to try to expose.

Corner 3s normally come from penetration forcing help and this is the case for most of the attempts the Heat allow. The team tries to get away with playing at least one below-average perimeter defender most of the time (although Tyler Herro’s injury, while a huge burden offensively, has allowed them to play more defensive lineups in the postseason).

And there will be times when the Celtics’ offense generates good looks from long distance. But the key for the Heat is to make them work for it. There are possessions where the Celtics get good looks after making four good decisions with the ball. Then there are these.

It’s another semi-transition possession for Tatum, who generates a corner 3-pointer for Horford without doing much of anything. Dewayne Dedmon isn’t on the team anymore, but this kind of easy blow-by and pass to the short corner has been a problem for the Heat all year. And if they make it this easy for Boston to generate looks from the corner, Miami will have to pray for the best shooting luck of any team in the playoffs.

That shooting luck hasn’t materialized for Boston’s opponents thus far in the playoffs. Boston leads the playoffs in catch-and-shoot percentage on 3s at 40.1%. Miami is 3rd at 39.7%. But Boston’s defense is much more adept at running shooters off the line.

Miami will have to do the same.

4. Can Big Al Find His Offense?

If Miami can’t contain the corner 3-point attempts from Boston, one of the players who will get the most opportunities is Horford. But that will only help the Celtics if Horford’s shooting touch comes back this series.

Horford shot a career-high 44.6% on 3-pointers this year, but that has cratered to 30.8% in the playoffs. When Boston’s offense is humming, it’s one of the hardest to guard in the league because there are no hiding spaces and everyone shares the ball.

But at 36, Horford’s offensive responsibility has declined, and he spends most possessions as a spot-up shooter, especially when playing with Robert Williams III. If he’s not hitting enough shots, Miami will choose him as the guy to leave open and help off whatever corner he is in with reckless abandon.

It’s a pretty simple part of the equation for this series. Horford is going to have opportunities to hurt the Heat with his shooting. If he can shake off a few bad rounds of shooting (and possibly focus more on offense without the uphill battle of guarding Embiid anymore), the Celtics will be able to exploit a weakness of the Heat.

If he continues to shoot poorly, Boston’s offense becomes a lot easier to guard.

5. Can Jimmy Keep Getting to the Line?

The Celtics are probably glad to be done playing Embiid for a host of reasons, but one of the biggest is all the times he went to the free-throw line.

Embiid averaged 8.57 free-throw attempts per game in the seven-game series, which was down from 11.7 attempts per game during the regular season.

But the Celtics have another tall order in this series, as Butler leads all players who played 10 or more games this postseason with 10.1 free-throw attempts per game. No one else in that group averaged more than 8.7 attempts.

We mentioned Butler’s ability to limit turnovers, but the other part of Butler’s efficiency is how often he gets to the line. And these playoffs he’s done that better than anyone.

Boston did a remarkable job in the two games Butler suited up against them in the regular season, limiting Butler took just three free throws in 75 minutes. They allowed him to shoot 7.7 attempts per game in the playoffs last year.

Butler has an impressive bag of tricks in the post and midrange (his ball fake is one of the best around), and he can use his strength to force the issue and draw contact. The Celtics will have to try to neutralize this by being disciplined and doing everything they can to not give Butler the matchups he wants and perhaps force Max Strus, Kyle Lowry and Bam Adebayo to beat them.

If a small guard or big man gets stuck on Butler on an island, he’s going to be able to draw contact.

Series Win Probability: Who Has the Edge?

In terms of the moneyline, sportsbooks have the Celtics, who have home-court advantage at the TD Garden, as the best bets (-145) and the Heat as the underdogs (+120).

But what is our model’s prediction for who will advance?

Eastern Conference finals win probability

This model calculates each team’s chances of making it to the NBA Finals and winning the title outright, based on thousands of simulations.

It incorporates the rankings from our adjusted team ratings (including overall adjusted team rating, adjusted offensive rating and adjusted defensive rating), accounts for recency bias (so, it gives more weight to teams playing well) and for how well teams performed against other good teams.

In this case, the model gives a substantial advantage to the Celtics, who own the league’s best adjusted team rating heading into the series. But the Heat, and Butler in particular, have shown an uncanny ability to ramp up their play when the lights are brightest in the NBA playoffs for multiple seasons now.

If they can do that again, we should be in for an entertaining series.

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