By Miles Wray

When LaMarcus Aldridge made his surprise jump in free agency to the San Antonio Spurs, one of the most pressing questions in the NBA last summer and fall were: How would Aldridge fit into the famously smooth Spurs offense? There was another lurking question -- perhaps an, even more, important one -- that could only be answered once Aldridge stepped on the floor in silver and black: How would he fit in on defense? Aldridge was joining a team that had been one of the top three defenses, by points allowed per possession, for three straight seasons (2012-15). In nine seasons in Portland, Aldridge had a combined Defensive Rating of 106. In 18 seasons in San Antonio, Tim Duncan had never posted a Defensive Rating higher than 101. 

As the NBA season turns to its home stretch, the Aldridge experiment is clearly a rousing success, and on both sides of the floor. San Antonio has won 84.9% of their games, which is not only the best rate of the massively successful Gregg Popovich era, but it’s also on pace to be one of the greatest seasons in NBA history. The Spurs are, indeed, dominant on offense, ranking third in the league in points per possession. That’s really, really good. But it’s not historic. What’s historic about this team is its defense. 

The Spurs are allowing 0.98 points per possession, which not only leads the league, but it leads the second-place Indiana Pacers by four points per 100 possessions. And Indiana is four points per 100 possessions better than the twenty-second-place New York Knicks. The gap between the Spurs and the next-best defense is the same gap that separates other elite defenses from below-average ones. That 0.98 points per possession are tied for the fourth-best team defensive rating since the three-point line was instituted in 1979-80 (excluding teams from the lockout-shortened 1999-2000 season). 

Aldridge is second on this team in minutes (to Kawhi Leonard). A player who is playing so much, and on such a great defensive team, cannot simply be “hidden.”

A huge portion of the Spurs’ defensive success comes from how they defend the pick-and-roll, the mechanism that ignites most offensive plays in today’s NBA. Popovich has the Spurs “Ice” pick-and-rolls, which is a defensive strategy where the bigger defender -- in many cases Aldridge -- focuses on stopping the ballhandler from penetrating into the key. In the example below, look at how Aldridge concedes about five feet of space to the offense, protecting the paint instead:

As Spurs assistant Ime Udoka noted in a preseason interview with BBall Breakdown, “We teach the ‘no middle drive,’ so footwork-wise we’re already in that position.” Notice how both Spurs defenders are angled to move the ballhandler towards the sidelines, cutting off the center of the floor. 

These are not new or novel defensive concepts. Tom Thibodeau’s Chicago Bulls (2010-2014) would use Ice to perfection. The following compilation, assembled by Michael Bowden while Thibodeau was in charge, shows the technique in motion, sometimes with the Bulls defenders audibly calling “Ice!” to one another. By prioritizing protecting the key, the defense gives the offense a host of problems:


Thibodeau did not innovate the Ice defense either, though. Here’s Popovich on his defensive philosophies in FIBA Assist Magazine in 2003:

My second rule is that the player with the ball can never penetrate to the middle of the court. Our goal is always to direct him to the baseline. If the defender of the player with the ball lets the penetration into the middle, I will immediately take that player out of the game.  

[...]

There are many players that have a good first step off the dribble and there are those that jump and shoot well at the end of the penetration. However, there are only a few that can shoot in the space between the start of the dribble and the position they finally reach under the basket. That’s because they have a defender by their side and another one, usually a tall player, that runs towards him to stop penetration to the basket.

While Popovich has held those same defensive goals in place for at least a decade-plus, they actually haven’t always been successful. On the eve of the 2012-13 season, Andrew McNeill of the Spurs blog 48 Minutes of Hell actually voiced his displeasure with the strategy, citing that San Antonio big men still allowed drives into the paint while also conceding mid-range shots. 

That was true then. And it isn’t true now because the Spurs now have a seven-footer who is agile on the perimeter as any in recent memory: Aldridge. Here’s Manu Ginobili praising Aldridge’s foot speed after a November victory:

Usually, we are a team that builds defensively, slowly. This year we started very well, very aggressively. The addition of LaMarcus gives us more size. He has quick feet to switch, to get in a better position quicker. 

Aldridge’s agility means that the Spurs are not necessarily at a steep disadvantage if he switches onto a smaller defender. Look at how the play from the still image above actually transpires. There is that brief moment when Aldridge displays perfect containing position for Ice -- but he also switches twice, including once onto a guard, until the shot clock runs out on the opponent:

Even a brief second that Aldridge can contain an opposing guard can provide his teammates enough time to collapse on the ballhandler and disrupt the play:


If there is no opportunity for the help to come, Aldridge commits to defending the guard for the rest of the possession:


So why hasn’t Aldridge been known for this type of defensive tenacity before? It might be that his offensive responsibilities in Portland were too great to maximize his effort defensively. So far, Aldridge is averaging 29.8 minutes per game with the Spurs -- the first time he has played under 34 MPG since he was a 21-year-old rookie in 2006-07. His usage percentage is at 25.2%, which is well above-average -- but still the lowest it’s been since the 2009-10 season. Once again, there is brilliance wherever you look with the Spurs: by putting together such a deep roster, San Antonio is able to responsibly lower Aldridge’s offensive burden, helping him be a better defensive player than he ever has been before.