MILWAUKEE — The NBA’s elite teams almost always have a singular, defining trait.

Golden State gives opposing teams headaches due to its ridiculous outside shooting. Cleveland’s players, as LeBron James and Kyrie Irving illustrated during the Finals, can get almost any shot they want in one-on-one matchups. The San Antonio Spurs, the gold standard for team play and consistency, have long drawn praise for their lack of egos.

Then there are the 18-16 Milwaukee Bucks, who, bizarre as it sounds, are quietly building a case for inclusion onto that short list of the league’s best teams.

As of Thursday, Milwaukee was just two games ahead of the ninth-place Washington Wizards and far from a lock to reach the playoffs. But for most of the season the Bucks have ranked among the league’s top-10 teams in both offensive and defensive efficiency, generally a loose prerequisite for a team to be a title contender. (Sixteen of the past 20 NBA champions, including each of the past six, finished in the top-10 in both categories. By contrast, no team with that profile has missed the playoffs since the 1974-75 season, when three teams did it in an 18-team league, according to ESPN Stats & Information Group.)

Unlike with the Warriors, Cavs or Spurs, the average fan might struggle to identify a particular trait about the Bucks, aside from their star player having a name that’s challenging to pronounce.

But spend a little time watching the Bucks and it becomes clear that Milwaukee’s defining characteristic is its weirdness. Its roster full of interchangeable, Stretch Armstrong-types goes outside the bounds of the NBA’s traditional parameters of play at both ends.

Still, Milwaukee is far from the first team to lean on its length and athleticism. “Positionless basketball” has been in vogue for a while now.

In recent years, the Big Three in Miami was unusually aggressive with how it tasked Chris Bosh with defending pick-and-rolls. The Brooklyn Nets turned their 2013-14 season around (and did so under current Bucks coach Jason Kidd) after injuries forced them to downsize to a quicker small-ball lineup that could switch assignments and jump passing lanes. And of course the Warriors can make life miserable for opposing offenses and impossible for opposing defenses with their range and versatility, particularly when they opt to use their Megadeath Lineup, with Stephen Curry, Andre Iguodala, Klay Thompson, Kevin Durant and Draymond Green.

No one is going to mistake these Bucks with the Warriors any time soon, or with the Cavs or Spurs, for that matter. But the Bucks’ combination of uncommon youth, length and style of play makes Milwaukee uniquely equipped to deal with teams that throw more traditionally constituted opponents into disarray. In other words, teams like Golden State.

The formula starts with the Bucks’ unusual youth and length at multiple positions. In Giannis Antetokounmpo (22 years old), Jabari Parker (21), Tony Snell (25) and John Henson (26), Milwaukee trots out four starters who are all 26 or under, and boast at least a 6-11 wingspan, making them one of the youngest and longest teams in the NBA. The Bucks use their length and athleticism to play a more aggressive, switch-heavy brand of defense than most teams.

They often gamble by overloading one side of the floor and using two players to blitz a pick-and-roll ball-handler, trusting that they’ll have enough back-end quickness to snap back into position before opposing players can capitalize by finding the open man for a clean look. (Milwaukee also sends aggressive help when teams dump the ball onto the block, explaining why the Bucks own the stingiest post-up defense in basketball, according to Synergy Sports.)

So many interchangeable defensive parts moving, switching and rotating in harmony has a suffocating effect on an offense. Milwaukee’s defense has forced opposing offenses to throw more passes than all but eight teams this season after leading the league in the stat the past two years, according to an analysis run by SportVU, and has pressed opposing clubs into the last four seconds of the shot clock — where offensive efficiency plummets due to rushed shots — more often than any other defense this season, per Synergy.

“Against them, you have to go in understanding that it may take several extra passes or multiple paint touches” in order to find a good shot, Oklahoma City Thunder coach Billy Donovan said ahead of a recent game against Milwaukee. “What appears to be an open shot often turns out to be a contested shot.”

The stat sheet seems to agree with Donovan. While the Bucks give up the fourth-most 3-point attempts per game — generally a bad sign for a defense — Milwaukee also contests 87 percent of opponents’ threes, the highest percentage in the league. As a result, it holds foes to 34.6 percent from 3-point range, tied for the NBA’s fourth-lowest mark. In other words, lots of attempts are not quite as open as they seem.

“Shooting is obviously huge,” said Henson, the Bucks’ best defensive big man. “But probably the best things to counter the shooting in today’s game are interchangeability and length. And we’ve taken the idea of building around length to another level.”

That’s a key trait in the NBA today. The commitment to flustering ball-handlers and ability to close out shooters help neutralize the floor spacing that teams like the Cavs and Warriors usually take advantage of.

While the Bucks have targeted length as a market inefficiency, that length comes at a cost.

For one, the Bucks’ lengthy, versatile athletes aren’t as gifted from long range. Last season, Milwaukee attempted the fewest threes in the league and made just 34.5 percent of them, below league average. (This is a big reason the Warriors are so special: They combine many of the same elements that make the Bucks unique with all that outside shooting.)

But this season the offense has increased its number of 3-point attempts per game by a whopping 53.5 percent while also increasing its conversion rate, led in part by Parker, who’s hit 39 percent of his triples while taking more than six times as many threes per game as last season.

“[Coach Kidd] told me [two years ago] that I was too reliant on my jumper and challenged me to work on my inside game first, then take what the defense was giving me on the outside,” Parker said in an interview, explaining that he and Antetokounmpo were essentially banned from taking threes when Kidd first got the job. But Parker said they’ve since been given the green light to fire away. (That inside-out mindset is an interesting one, given that Kidd himself developed into a much better shooter as his own career progressed.)

In any case, Parker and the Bucks are still working through a handful of issues. The former Duke star has improved as a defender, but still gets beaten off the dribble far too frequently on the wing, leaving the team vulnerable at the rim at times. And despite the club’s ability to get out to shooters quickly, it’s not ideal that the Bucks surrender the highest number of corner threes in the league, since those shots are among the most valuable in basketball.

And even after Antetokounmpo’s heroic last-second shot to beat the Knicks on Wednesday, Milwaukee’s stats in crunchtime (when the score is within 5 points in the last five minutes or overtime) are among the worst in the NBA.

But things are beginning to come together. The awkward fit with scoring big Greg Monroe has been alleviated with a move to the bench, where his limited rim protection isn’t as much of a liability. After struggling to score last season, Milwaukee has found success in having Antetokounmpo bring the ball up the floor himself after grabbing a board instead of having to look for a teammate. (The Bucks rank fifth in fastbreak points, despite ranking 20th in possessions per game; impressive given that the four teams ahead of them in transition scoring — Golden State, Phoenix, Oklahoma City and Houston — rank among the top-10 in pace.)

And the club could even get injured swingman Khris Middleton back toward the end of the season; potentially a big lift for the Bucks, given that he was arguably their best player at times the past few seasons.

The teamwide developments, though, have been mere icing on the cake, as no one in the organization saw Antetokounmpo producing a season anywhere near this impactful so soon.

His defense, particularly as an occasional rim protector, has been a revelation. Antetokounmpo, despite being a wing player, is near the top of the defensive leaderboards among players who defend at least four close-range shots per game, according to SportVU. But understandably, his offense draws the lion’s share of the attention, both because of his unconventional point-guard play and the gaudy numbers he’s posted.

He currently owns career-high marks in total-shooting, rebounding, assist, block and steal percentage — and a career-low turnover percentage — all while handling the ball more and using a much greater share of Milwaukee’s possessions in his fourth season.

Even with his rapid ascension in mind, it might still seem wild to consider Milwaukee among the NBA’s best. But give it time. If the young Bucks continue on their current trajectory, and their gambles on length and versatility continue paying off, the thought may not seem so far-fetched this time next year.

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