Inside the Heat’s stunning three-point regression and what data shows. And a Herro update

It ranks among the great mysteries of these NBA playoffs: Whatever happened to the Heat’s three-point touch?

No team shot threes as accurately as the Heat during the regular season, with Miami closing at 37.9 percent, just ahead of the Hawks and Clippers at 37.4 percent.

But in postseason, the Heat is shooting just 31.2 percent on threes, which is 13th among 16 playoff teams and by far the worst among the conference finalists.

By comparison, Dallas is shooting 37.9 percent in these playoffs, Golden State 37.8 percent and Boston 36.5. Those three conference finalists rank third, fourth and seventh in playoff three-point shooting.

Miami’s three point shooting has been even worse in this series: 29.2 percent. Miami shot 7 for 45 on threes in Game 5 (15.6 percent) - the second-lowest three-point shooting percentage by a team in NBA playoff history (minimum 40 shots).

“Those open threes are the shots we’ve made all year long,’’ Erik Spoelstra lamented.

Asked if he’s surprised by the Heat’s massive three-point regression in these playoffs, Celtics coach Ime Udoka indicated two factors are in play: the Heat simply missing shots and Boston wearing on Miami.

“We’ve been fortunate at times with offensive kicks and rebounds that they usually get a lot of threes on; they’ve missed,” Udoka said. “And having a well balanced team makes teams have to guard [us]” and that can take a toll on a team’s energy and shooting.

Udoka said his defenders - long and active - can wear on opposing players and the result is opposing players are not often “getting a clean look. When they do get a clean look, they feel rushed. As we make them defend on one end and wear on them defensively, it [leads] to missed shots [by the Celtics’ opponent]. It’s not just a coincidence teams are missing.”

The harrassing nature of Boston’s defense - and ability to execute switches with a bunch of skilled defenders - “makes those shots a little more stressful when they do get open looks,” Udoka said.

In the playoffs, Jimmy Butler and P.J. Tucker are the only Heat regular rotation players shooting threes more accurately than they did in the regular season, with Butler’s percentage rising from 23.3 to 32.1 (18 for 56) and Tucker from 41.5 to 44.7 (21 for 47).

But Butler and Tucker were each 1 for 5 on threes in Wednesday’s 93-80 Game 5 loss.

Duncan Robinson, who has received erratic playing time in these playoffs, is shooting 39.1 percent, compared to 37.2 in the regular season. But here’s the caveat: He’s just 10 on 37 on threes after shooting 8 for 9 in Miami’s first playoff game against Atlanta.

Most of their teammates have experienced significant three-point dropoffs from the regular-season.

Tyler Herro has plunged from 39.9 percent to 23.2 (16 for 69). That includes 1 for 14 in this series before missing the past two games with a groin injury.

Kyle Lowry has dipped from 37.7 to 20.5 percent (8 for 39).

Max Strus - who shot 41 percent on threes during the regular season - is at 33.1 percent after going 0 for 11 on threes in the past two games. Strus has attempted by far the most three-pointers of any Heat player this postseason with 127, with Gabe Vincent next at 76.

Vincent is at 31.6 percent on postseason threes, down from 36.8 during the regular season.

And Victor Oladipo (41.7 percent to 29.4 percent) and Caleb Martin (41.3 to 28.1) also have dropped off dramatically from distance.

And here’s what’s surprising: According to the NBA’s tracking data, the Heat’s threes are being defended tightly on only 9.5 percent of their attempts in these Eastern finals, compared with 8.6 percent in the regular season.

Per NBA.com, when there is a Celtic within two feet of a Heat shooter, Miami is 0 for 3 on threes against Boston, compared with 10 for 23 when that happened during the entire regular season for Miami.

When a Celtic defender is within two to four feet, the Heat is shooting 30.8 percent on threes (12 for 39), compared with 33.5 percent in all Heat games during the regular season.

And this is significant: When the nearest Celtics defender is 4 to 6 feet away from the Heat shooter, Miami is shooting 22.2 percent on threes (16 for 72), compared with 37.3 percent during the 82-game season.

HERRO UPDATE

Herro, who has missed the past two games with a groin injury, is listed as questionable for Game 6.

Asked if he might play on Friday, Spoelstra said Friday evening: “I don’t know yet. He still has to do his treatment tonight. We’ll see him tomorrow at shootaround.”

Also listed as questionable: Lowry, Strus and Vincent (all because of hamstring strains) and Tucker (knee irritation). Spoelstra said he expected everyone who played Wednesday to be available Friday. Everybody played Wednesday except Herro.

▪ Wednesday’s game marked just the fourth time that a starting backcourt was held without a field goal in a playoff game, with Strus closing 0 for 9 and Lowry 0 for 6.

The previous times that happened: Wilbur Holland and Norm Van Lier with the Bulls (1977); Sam Cassell and Trenton Hassell with the Timberwolves (2004) and Kentavious Caldwell-Pope and Dennis Schroder with the Lakers in 2021.

Lowry and Strus are a combined 1 for 28 from the field and 1 for 19 on threes over the past two games.

▪ Bam Adebayo’s 18-point, 10-rebound effort in Game 5 was his 17th career postseason double-double, moving him past Udonis Haslem into fourth place in the Heat’s all-time playoff double-double list. Only LeBron James (31), Dwyane Wade (22) and Chris Bosh (18) have produced more postseason double-doubles for the Heat.

▪ Quick stuff: The winner of Game 5 of a 2-2 series has gone on to win the series 81.8 percent of the time…. In this series, Butler has scored 77 of his 97 points in the first half… Strus has missed 16 shots in a row from the field.