Detroit Pistons only going to trade if it obviously makes team better by Braden Shackelford

The Detroit Pistons had a top-five defense over the first 21 games, and then Reggie Jackson returned. What is the truth behind their precipitous drop?

The Detroit Pistons have been a frustrating and confusing mess for much of the past month and a half. Over the first 21 games while Reggie Jackson recovered from knee tendinitis, Ish Smith quarterbacked a mediocre offensive attack but the Pistons had a stellar top-five defense, allowing just 101.1 points per 100 possessions.

That didn’t make much sense. Smith is no defensive stalwart, and the rest of the starting unit comprised a foursome that, along with Jackson, posted fairly pedestrian defensive numbers a year ago. After acquiring Tobias Harris via trade last February, the Pistons starting unit of Jackson, Kentavious Caldwell-Pope, Marcus Morris, Harris and Andre Drummond allowed 107.2 points per 100 possessions. That’s not terrible, but it’s not great, and the only change was a swap of Jackson for Smith.

By no metric is Smith defensively superior to Jackson. They’re both pretty mediocre on that end of the floor. However, when Jackson returned, the bottom seemed to drop out for the Pistons’ defense. The Pistons have gotten lit up defensively and have yielded 107.9 points per 100, 20th best in the NBA since his return.

An obvious but lazy narrative sprang to life: Reggie Jackson must just be garbage at defense. After all, he wasn’t anything special defensively to begin with, and now he’s recovering from a knee injury and trying to get his game legs back against players who had been going hard for two months.

That had to be it. Reggie Jackson is awful at defense.

As it turns out, like many things with the Pistons this season, the truth is somewhat more complicated.

To figure out why the Pistons have fallen so hard defensively, we need to start by looking at what has NOT changed, and then we’ll get into what has.

First off, one of the best things Smith brought to both the offense and the defense was that he took excellent care of the ball. He rarely turned it over and as a result, opponents almost never got easy transition baskets. Over the first 21 games before Jackson’s return, the Pistons yielded just 11.8 points per game off turnovers, best in the NBA. They also allowed only 9.7 points per game in transition, by far the best mark in the NBA.

In addition, they controlled second chance points, limiting their opponents to an NBA-best 10.6 second chance points per game, and they surrendered 39.9 points in the paint per game, fifth-best in the NBA. These numbers are certainly less a result of Smith’s leadership than they are due to Andre Drummond, Jon Leuer, Aron Baynes and company patrolling the paint effectively, but they’re all a piece of this defensive pie.

We’ll contrast this against what the Pistons have done in those categories since Jackson returned 23 games ago.

Over those 23 games, the Pistons have the fourth-best points per game off turnovers, yielding 13.9 (+2.1 compared to the era of Ish). This is because while Smith took good care of the ball with a turnover percentage of just 13.5, Jackson isn’t far behind at 14 percent. Their transition points against have remained static at 9.7, and their second chance points against have dropped precipitously to 8.1, 2.5 points better. Their points allowed in the paint have dropped to 39.3 per game, fourth-best in the NBA.

By all of these metrics, the Detroit Pistons defense has held or improved. So what’s different, and how can we find these additional 6.8 points per 100 possessions?

Buckle your seatbelt, because this is where things get weird.

Before Jackson came back, the Pistons yielded a three-point percentage of 34.2 percent. That was fifth-best in the league. After his return, that three-point percentage skyrocketed to 39.5 percent, second-worst in the NBA.

To break things down further, since Jackson’s return, only one of the Pistons’ five most-used lineups has allowed a three-point percentage of LESS than 45.7 percent. These five lineups have spent a total of 444 minutes on the floor. In fact, the Pistons’ default starting lineup of Jackson, KCP, Morris, Harris and Drummond have yielded a three-point percentage of 45.7 percent over the 213 minutes they’ve played together. The secondary starting unit in which Harris is replaced by Jon Leuer is yielded 46.7 percent over 94 minutes.

To put into context just how good 45.7 and 46.7 percent are from three-point range, Joe Ingles leads the NBA with 46 percent. Stephen Curry hit 45.4 percent of his threes last year. In other words, over the 307 minutes these units have been on the floor together, opposing shooters are hitting threes with roughly the same efficiency that matches that of the best shooter in the NBA this year, and right around what Curry hit last year.

Needless to say, these numbers are preposterous, and Haralabos Voulgaris weighed in and agreed that there is a great deal of negative variance working against the Pistons here.

As you mentioned this is pretty random. The expected value of the shots the unit has given up is around 36.5% (based on shooter and defense) https://t.co/yDZiaXdY7T — Haralabos Voulgaris (@haralabob) January 19, 2017

It’s worth noting here that the most important metric when it comes to three-point defense is NOT three-point field goal percentage, but three-point attempts allowed. In essence, the best defense is one that simply doesn’t allow the shot to go up in the first place. That being the case, the Detroit Pistons have actually demonstrated excellent perimeter defense.

In the pre-Jackson era, the Detroit Pistons allowed 25.2 three-point attempts per game, and since his return the Pistons are allowing just 23.6. That’s the fifth-best mark in the NBA over the last 23 games. In essence, the Pistons are doing the right things in the department that is killing them. In fact, their opponents only attempt 29 percent of their total field goals from three-point range against them. That mark is sixth-best in the league.

So then, what is the real-world damage being caused by the fact that they are defending threes well, but a disproportionate percentage are falling?

Pre-Reggie, the Pistons allowed 8.6 threes per game on 25.2 attempts. That works out to 1.023 points per shot. Multiplied by 25.2 shots, that’s 25.7 points per game that opponents were scoring from behind the arc. To get a touch more advanced, if we adjust for pace (the Pistons and their opponents had an average of 96.4 possessions per game), the Pistons yielded 26.7 points per 100 possessions.

Post-Reggie Jackson’s return, the Pistons are allowing 9.3 threes per game on 23.6 attempts. That works out to 1.182 points per attempt. Multiplied by those 23.6 shots, that’s 27.9 points per game directly from three-point attempts. Adjusted for pace (the Pistons and their opponents have played an average of 96.2 possessions per game since Jackson’s return), the Detroit Pistons have yielded 28.9 points per 100 possessions.

Right off the bat, that’s 2.2 points per 100 possessions that we can account for, simply from three-pointers going in a ridiculously disproportionate amount.

What does 2.2 points per 100 possessions mean? If those points were shaved off the Pistons’ defensive rating over the past 23 games, the defensive rating of 105.7 would jump from their current rank of 20th all the way up to ninth. That would place them ahead of the Toronto Raptors, Atlanta Hawks, and Washington Wizards over the last 23 games.

There are a lot of things working against this team. They haven’t been healthy as a unit for a single game since the start of the season. It’s a young and immature team that can get down on themselves easily, and if there’s anything that can get a young team down, hitting two or three three-pointers in a row against them will. Bad breaks, bad timing and bad luck have forced the Detroit Pistons out of the top eight seeds in the Eastern Conference. Unfortunately, at this point only the lifting of these curses will allow them to push back in.