The NBA playoffs keep getting smaller. The Warriors took the league by storm a few years ago with their Lineup of Death, when they took their traditional big men off the floor and played five perimeter players at a time. Now everyone else is catching up. The 76ers downsized around Ben Simmons, and the Bucks downsized around Giannis Antetokounmpo in Game 1 of their respective first-round series. There’s nowhere to hide a center on defense when Simmons and Giannis, two of the most dynamic young players in the NBA, are surrounded by four 3-point shooters. The only way to respond, as the Heat showed in Game 2 of their series with Philadelphia, is to downsize with them and beat them at their own game.

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The Sixers were forced to go small out of necessity. Joel Embiid, their star center, has been out the last few weeks while recovering from a concussion. They benched Amir Johnson, his replacement, when they were down four points at halftime of Game 1 and blitzed Heat center Hassan Whiteside off the floor behind a barrage of 3s. Miami turned the tables in Game 2 on Monday, playing Whiteside and his backup, rookie Bam Adebayo, only 25 combined minutes, compared with 33 in Game 1. They were just as small as the 76ers the rest of the time, playing some combination up front of Kelly Olynyk, James Johnson, and Justise Winslow.

Milwaukee waited until the final minutes of its Game 1 loss to Boston to pull the trigger on a similar lineup. They were down 86-82 when they moved Giannis to the 5 with 3:11 left in regulation. The Bucks were never able to get much traction on offense with either John Henson or backup center Tyler Zeller on the court for most of the game. With Milwaukee’s superstar at center, Boston couldn’t send a second defender to Giannis without leaving someone open at the 3-point line, and none of its players can stay in front of him in a one-on-one matchup. Game 2 of their series on Tuesday will likely look a lot like the Miami-Philly Game 2 on Monday, with both teams playing four or five 3-point shooters for long periods of the game.

The Bucks and the 76ers didn’t play their super-small-ball units much in the regular season. According to the lineup numbers at NBA Wowy, Giannis played 191 minutes this season without one of the six traditional big men on his roster, while Simmons played 165 minutes without one of the five on his. Considering how much they do on offense, it’s hard to ask them to spend too much time anchoring the defense and banging against bigger players in the paint. The regular season is a six-month grind, and their teams don’t want their young stars putting too much wear and tear on their bodies. It’s the same reason why Golden State has traditionally waited until the playoffs to lean heavily on their Lineups of Death, with Kevin Durant and Draymond Green at center.

The traditional big man has become like a back-of-the-rotation starter in the baseball. There’s real value in having a pitcher who can take the mound every five days and throw more than 150 innings in a season, even if they are only average. However, in the playoffs, where the importance of every inning is magnified, MLB teams need to ride their best pitchers as long as they can. A manager could never use his best relievers in the regular season in the same way that he does in the playoffs: Their arms would blow out from the strain. In the same way, an NBA coach would burn out his best small-ball 5s if he asked them to play big minutes for 82 games at the position. The calculus changes when teams are fighting for their lives in the postseason.

The opportunity cost of playing an average center becomes too high. Whiteside and Adebayo are perfect examples. They aren’t focal points of the Miami offense, so they can’t punish smaller defenders inside, while their lack of shooting range allows the Philadelphia defense to pack the paint. On the other side of the ball, they aren’t as comfortable guarding the 3-point line. Even a quicker big man like Adebayo, who has the footspeed to defend on the perimeter, doesn’t have the same instincts to help, recover, and switch screens as guys like Winslow and James Johnson. There’s room for only one non-shooter in a lineup, and Winslow, who can initiate the offense and match up with Simmons, is more useful in that spot than either of the Heat centers.

The best way for a big man to stay on the floor is to play like a guard. Celtics center Al Horford can thrive in a small-ball game because he’s been a small-ball 5 his entire career. He’s shooting 42.9 percent from 3 on 3.1 attempts per game this season, and he’s averaging 4.7 assists a game on only 1.8 turnovers. He’s even been given the primary assignment on Giannis on defense, although he wasn’t nearly as effective in that role in Game 1 without a second big man zoning the paint behind him. However, even if Boston head coach Brad Stevens has to move a wing onto Giannis when Milwaukee goes small, he can still cross-switch Horford onto one of the Bucks’ other guards, who may not be able to punish him from behind the 3-point line.

The question for the Bucks in Game 2 is whether they can consistently stretch the floor even when they go small. They were 25th in the NBA in 3-point attempts per game (24.7) this season and 22nd in 3-point percentage (35.5). Eric Bledsoe and Khris Middleton, their two secondary scorers, are both more comfortable in the midrange, while Tony Snell didn’t look ready for the moment in Game 1. Snell shot 1-of-4 from the field and 0-of-3 from 3 in 33 minutes and passed up several open looks late. The Celtics will likely dare him to knock down shots Tuesday. There’s no point in playing small if those smaller players aren’t spreading the floor and opening up driving lanes.

The potential downside of small ball is clear: Teams need a lot of perimeter depth to survive playing that style for most of the game. Simmons, Dario Saric, and Ersan Ilyasova were all limited by foul trouble in Philadelphia’s Game 2 loss, and 76ers head coach Brett Brown didn’t have many viable replacements on his bench other than Marco Belinelli. Neither of his two backup point guards, T.J. McConnell and rookie Markelle Fultz, are 3-point threats, and he doesn’t seem to trust younger wings like Timothe Luwawu-Cabarrot, Furkan Korkmaz, and Justin Anderson. He wound up having to give Amir Johnson a lot of playing time in the second half, and he was victimized by smaller Miami players on the perimeter, in a reverse image of Game 1.

Both first-round series could be decided by which team has more options on the perimeter. The Bucks may need to turn to rookie Sterling Brown, a consistent 3-point shooter (35.2 percent from 3 on 1.7 attempts per game in the NBA, and 45.1 percent in his four years at SMU) and versatile perimeter defender who moved into the rotation in the second half of the season but played only two seconds in Game 1. Players like Brown are worth their weight in gold because they can fill in the gaps on both sides of the ball. They stay out of the way on offense, occupying a defender on the perimeter, and they can slide around the floor on defense, a necessity when offenses are running multiple pick-and-rolls and swinging the ball from side to side. Any weak spot in a lineup will eventually get exposed in a small-ball game.

The difference in the 76ers and Heat series is that Embiid, who could return to the lineup as soon as Thursday for Game 3, is dominant enough to swing the game back the other way. It’s hard to go small against Embiid, a 7-foot, 250 pound Goliath with an elite post game who can destroy smaller players on the block. Unlike the other big men in either series, Embiid is one of the primary options in the Philadelphia offense, with an eye-popping usage rate of 33.4. He’s also an elite defensive player who can wall off the paint and slide his feet on the perimeter. The Heat can either try to run Embiid off the floor in the same way that Philadelphia did Whiteside, which will not be nearly as easy, or bring their centers back in and play a more traditional game.

In all likelihood, there will be two different types of games within the game in that series: a bigger one when Embiid is in, and a smaller one when he is out. The 76ers won’t need to play Amir Johnson or Richaun Holmes, their two backup centers, when Embiid is resting. Brown will likely stagger the minutes of Embiid and Simmons so that one is always in. They can play a more traditional inside-out game with Embiid, and then a faster and more perimeter-oriented game with Simmons surrounded by 3-point shooters. Miami doesn’t have the same type of star power to dictate matchups, which could be its undoing.

The most intriguing possible second-round matchup would be between Milwaukee and Philadelphia. There would be huge stretches of that series where Giannis and Simmons go toe-to-toe in the lane, with the other eight players on the floor spread out along the 3-point line. Both teams will have to answer questions about their supporting cast to get out of the first-round, but that showdown seems inevitable—if not in this season, then surely at some point in the near future. Small ball is here to stay, and only the very best big men will survive. After all, Simmons (6-foot-10 and 230 pounds) and Giannis (6-foot-11 and 222 pounds) are big enough to have been centers even a generation ago. There’s no reason to play an average big man next to them who just gets in their way.