Spurs' biggest offseason signing has yet to play a single minute

Lost in the San Antonio Spurs drafting Dylan Harper and Carter Bryant, signing De'Aaron Fox to a max extension, and bringing in Luke Kornet was an equally impactful move. The Spurs signed coach Sean Sweeney to be their lead assistant coach and defensive coordinator.

The results have been night and day, with the Spurs boasting the fifth-best defensive rating in the NBA this season after ranking 25th last season. That is only behind the defending champion Oklahoma City Thunder, who took years to cultivate an elite defense.

Even without Jeremy Sochan for the team's first seven games or Kornet, who missed seven of the team's first 10 contests, Sweeney has cooked. They rank fourth in blocks thanks largely to Wembanyama, who serves as the backbone of Sweeney's system, and eighth in steals.

Under Sweeney, the Spurs' perimeter defense has been far more aggressive, putting pressure on offenses, leading to more mistakes and, more importantly, more stops.

The Spurs have been dominant defensively this season

Sweeney has plenty of defensive options to work with, including Stephon Castle, Devin Vassell, Julian Champagnie, Sochan, and Carter Bryant. That is an embarrassment of riches and allows for plenty of mixing and matching.

Having a lid on the rim with Wembanyama patrolling the paint allows for the Spurs' perimeter players to both stay home on their defensive assignments and also take more risks in hopes of drumming up turnovers.

Vassell has been noticeably more active defensively, playing at a level not seen since his second season. He has reverted back to being a good team defender, with his mobility and attention to detail helping make him a plus on that end once again. Even Keldon Johnson has been especially active defensively.

Although he has always played hard on that end of the floor, he hasn't always been the most impactful defender. This season, his tenacity has been a welcome sight, with San Antonio having good defenders around him to cover for any shortcomings he might have while also helping to maximize his strengths.

Even at just 6'4, he has been crashing both the offensive and defensive glass, helping either to extend possessions or end them. Equally as important, his sturdy frame allows him to physically guard bigger players.

The Spurs have the personnel and coach to shut down teams

It isn't just San Antonio having an elite rim protector and guards and wings who can defend around Wembanyama that makes them so dangerous on the defensive end. It's their ability to mix and match.

Against the Chicago Bulls, San Antonio rallied from 14 down midway through the third quarter by grabbing the bull by the horns. They employed a big lineup that featured De'Aaron Fox, Castle, Harrison Barnes, Kornet, and Wembanyama.

That jumbo lineup featured four players 6'6" or taller and three players 6'8" or taller, including two 7-footers. With that big lineup, San Antonio kept the Bulls off the offensive glass and finally began challenging Bulls threes after initially giving up plenty of wide-open looks from outside.

Chicago stopped attacking the paint with Wembanyama and Kornet lurking, allowing defenders to stay home on their man, forcing the Bulls to shoot over length. As a result, they went scoreless for most of crunch time and hit just two shots in the final five minutes compared to San Antonio hitting seven.

The Spurs can mix and match defensively

What's more impressive is the fact that San Antonio didn't have Sochan in the game. Though he can close games, giving them a big stopper who can shut down guards, wings, and forwards alike.

Even so, Castle has proven to be almost as versatile defensively and has been tasked with guarding a multitude of talented offensive players. In fact, he has usually gotten the better of the matchup, making him a hugely impactful player on the defensive end.

Once San Antonio is at full strength and has had a chance to fully set their rotation, expect for the defense to only improve. After all, several of the Spurs' best defenders missed either the preseason or several games to start the regular season.

And once everyone is fully settled into the lineup, San Antonio could reach an even higher level defensively, which could spell trouble for the rest of the NBA.