The Spurs’ second unit is the main reason for their success

The Spurs have changed their identity this season, especially as it concerns the starting lineup. They are now younger and smaller, having surrounded their two veterans stars with the athletic draft selections of years past.

Their transformation has rightfully gotten a lot of attention, but their success, as it has for the past three years, has been more tied to another core that hasn’t changed all that much. The bench trio of Patty Mills, Rudy Gay and Jakob Poeltl has been at the center of everything the Spurs have done well this season, as they have before.

As exciting as it has been to watch Lonnie Walker IV, Keldon Johnson and Dejounte Murray take a leap this season, the starting lineup has actually gotten worse than it has been in the recent past. This year’s starters have one of the worst net ratings in the league even with the youngsters on board, ranking as the worst unit in the top 10 in minutes played this season despite the team’s strong record. Last season starters were awful on defense but broke even because of their great offense, and in 2019 they actually posted a modest positive net rating, at least when the lineup featured Gay.

Meanwhile, the Spurs’ bench units have been excellent throughout. First with Davis Bertans flanking Mills and Poeltl, and then swapping Gay for Bertans when he was traded. In terms of on/off numbers, essentially all members of the bench have posted extremely positive figures while the starters have had often disastrous ones. Even last season’s punching bag, Marco Belinelli, posted good splits. It seems that Gregg Popovich has been able to figure out how to make the bench work even with moving pieces, but never found the right recipe when it came to the starting unit.

The reason why might just be the players. While Mills, Gay and Poeltl are not necessarily more talented than, say, LaMarcus Aldridge and DeMar DeRozan, they don’t have overlapping skills or play similar positions, which makes them fit well with each other. On offense, they simply don’t get in each other’s way, as Mills is a shooter, Gay mostly a stretch forward who can play on and off the ball, and Poeltl is a screener who doesn’t need touches. What that group needs is a primary ball handler and creator, which has made them a perfect fit for DeRozan and now Dejounte Murray to run the show next to a perfect supporting cast, to great success.

Yet as impressive as the ease in which the offense works in the second unit not matter who surrounds the main core really is, it’s nothing compared to the surprising excellence the bench has routinely shown on defense in recent years. After all, Mills and Gay are good scorers who can space the floor, and Poeltl is a good screener and dive man. They are supposed to grease the wheels of a good offense. The defensive prowess of at least the two perimeter guys, however, is less obvious, but there nonetheless, and fueled by sheer activity.

Patty Mills is an absolute pest on the ball, using his quickness to recover whenever his anticipation doesn’t allow him to get skinny on screens. The Spurs have even used him both this season and in the past on star perimeter wings much bigger than him to wear them down before help is sent.

Gay is strong enough to handle power forwards and utilizes his knowledge of the game to do the little things off the ball that disrupt the opponent’s offensive flow, like using his long arms to get deflections (third on the team in total deflections behind Dejounte Murray and Devin Vassell) or doing something as simple as poking away at entry passes.

Then there’s Poeltl, who might just be the most underrated defensive center since Tiago Splitter. Poeltl allows opponents a meager 42 percent on attempts close to the rim when he’s the primary defender, the same as Defensive Player of the Year candidate Myles Turner, which makes him an elite rim protector despite lacking gaudy block numbers. In general, opponents shoot over nine percentage points worse when Jakob is the closest defender, slightly better than Turner’s differential. Those numbers are not always the most reliable proof of excellence, but with Poeltl they line up well with what anyone can see from watching the team play. His presence changes games for San Antonio on the defensive end, and not only because he’s usually replacing the increasingly defensively-challenged Aldridge.

The Spurs’ second unit is unquestionably among the best in the league, and only getting better. Derrick White is currently coming off the bench, joining Devin Vassell at the wing. Even if White eventually returns to his starting spot, Lonnie Walker IV will likely get his slot with the bench mob. There’s no reason to believe the second unit will be anything but one of San Antonio’s biggest strengths this season, as it has been in the past, unless Popovich decides that he needs some of the talent that he keeps in the bench to join the starting lineup.

For now, and at least until next offseason, when both Mills and Gay will become free agents, the Spurs will continue to have an edge whenever both teams’ starters take a break. Whether having a great bench can be enough to make up for featuring an as-of-now ineffective starting lineup remains to be seen, but it’s comforting to know that there’s a safety net in place to prevent the now expected early game tumbles from becoming fatal.