The Spurs are .500 and a few games outside of the playoff bracket in the West. Having traded disgruntled Kawhi Leonard in the summer for DeMar DeRozan, San Antonio in a way doubled-down on an offense focused on mid-range jump shooters.

The Spurs already had LaMarcus Aldridge, the rare modern big man who just simply never stretched his range beyond the three-point line. DeRozan famously prefers to drive the lane or pull up from 20 instead of firing up threes. The style extends to the team’s No. 3 option, Rudy Gay, as well: he’s become more willing to take triples, but only marginally.

As you might expect, the Spurs are dead last in the league in the percentage of field goal attempts that come from long-range, at 27 percent. (This is a better measure that three-point attempts per game because it accounts for pace and overtime differences.) You’ll also be unsurprised to learn that almost no one gets a bigger share of its points from the mid-range: the Spurs rank No. 2 at 19.1 percent, a sliver behind the Warriors’ 19.2 percent.

So in an era of ever bigger appetites for threes, and given the supreme math advantage exploited by teams like the Rockets and Warriors in recent years, it’d be understandable if you’d looked at the Spurs’ disappointing record and their reliance on long two-pointers and think they are related.

They are not.

The Spurs’ offense, despite snubbing the efficient three more than any other team and relying more on the inefficient mid-range jumper than almost any other team, is pretty good, ranking No. 9 in offense at 110 points per 100 possessions. The Spurs are on track to have their best or second-best offensive season in franchise history. The offense has improved about three points per 100 possessions over last season’s version despite becoming more reliant on the mid-range and less interested in threes.

The Spurs’ problem — shock of all shocks — is defense. San Antonio sits at No. 24 in defense, giving up more than 110 points per 100 possessions, about a full point worse than league average.

This is new phenomenon for the Spurs, who under Gregg Popovich have regularly ranked in the top five in the league in defense, whether they were in the championship conversation or a slight down cycle. The defense has been a constant, yet it’s not there this season.

That’s worth exploring. Why suddenly is the Spurs’ defense unreliable?

San Antonio ranked No. 4 in defense last season, about four points better than league average. Of course, Kawhi Leonard is one of the most talented defenders of his generation, but he played just nine games last season. But there was another player the Spurs traded to Toronto who matters a lot for this conversation: Danny Green.

Green made second team All-Defense two seasons ago, and has a good reputation on that end. He played a lot of minutes for the Spurs; he featured in San Antonio’s top three most used lineups, two of which had incredible defensive numbers and the third of which was a few points better than league average on that end.

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But it’s not just Green. There are two more names you find in those strong defensive, high usage Spurs lineups from last season: Dejounte Murray and Kyle Anderson. Murray tore his ACL in the preseason, taking a top defensive point guard out of the lineup and putting San Antonio is a real rotational bind. The Spurs let Anderson go in restricted free agency in the summer, declining to match a 4-year, $37 million deal offered by the Grizzlies.

The combined effect of losing Murray to injury, Anderson to free agency, and Green in a trade has badly hurt the Spurs’ defense.

Their minutes in those most-used lineups have been replaced by those from DeRozan (an OK defender, though not to the level of Green), Bryn Forbes, and Dante Cunningham. Derrick White is getting more minutes with those top lineups than Patty Mills, who is more often running the offense on reserve-laden lineups.

If those players can’t find a way to adjust and defend more effectively, there aren’t many solutions on the roster. Jakob Poeltl, who also came over in the Kawhi trade, has strong on-off defensive numbers, but Popovich isn’t playing him much. You wonder if Popovich can find a way to get even more Mills minutes with the starters without killing bench production.

This is all completely foreign to San Antonio. Whether he has legendary defenders like Tim Duncan and Kawhi, or whether he has scrap heap stars like Bruce Bowen and Dewayne Dedmon, Pop always puts together a solid defense. He can’t find the right magic this season.

But if he does and the Spurs’ defense turns around with the offense holding, San Antonio should be able to make the playoffs and maybe even cause a little heartburn for opponents once there. After all, with the whole league embracing the three-pointer, teams will have to adjust mightily to guard the Spurs’ mid-range attack in a playoff series.

There’s always an advantage to being the team that zags.