The Trail Blazers were bad at defense last year. Not as bad as you might think– they were 16th in the league in defensive rating, just below average. Even still, a mediocre defense basically precludes you from winning a title, so let’s talk about it.
Stats people break basketball wins into the Four Factors: shooting efficiency, turnovers, rebounding, and free throws drawn. On defense, the Trail Blazers ranked 7th in effective FG% allowed, 13th in defensive rebounding, and 7th in free throws allowed. Pretty good on all three counts. The problem is that they ranked dead last in turnovers forced, which dragged their defense down into the bottom half of the league.
Out of curiosity, I pulled up a list of all the defenses in the last 10 years to force turnovers at a rate below 12.0%. It’s a mess. The list features two elite defenses (the 08-09 Spurs and Rockets), one good defense (the 2008 Mavericks), and two average defenses (the 2012 Lakers and the 2005 T-Wolves). The other twelve teams on the list were below average or else complete train wrecks.
Of those five good defenses, there is not much to provide hope for the Trail Blazers. The Spurs had 32-year-old Tim Duncan, still at the height of his powers. The Rockets featured Yao Ming, in his last great year (and really his last year before injuries took over). The Wolves had Kevin Garnett in his prime, and the Lakers had Andrew Bynum, before he became the ghost story young coaches are told about to keep them in line. The only team I can’t make heads or tails of is the Mavericks. Devin Harris-Jason Terry-Josh Howard-Dirk Nowitzki-Erick Dampier doesn’t seem like a great defensive core, does it? Weird. They were only 9th in the league in defense, anyway.
So it looks like if you’re planning to never force any turnovers, you either need to have an elite rim protector/huge dude or be the ‘08 Mavericks. Barring those, your defense will be bad. As nice as Robin Lopez is, it looks like the Trail Blazers’ better start forcing more turnovers. So how feasible is that?
Below is a graph. It’s not that complicated, so bear with me. The x-axis charts how much each team’s TOV% rank improved. The y-axis charts the change in defensive rating rank. What’s tricky is that a low-numbered rank is a good thing, but I ignored that. A +8 on the graph indicates that a team improved 8 spots.
The good news is that no team got worse at forcing turnovers. A lot of these teams started at 30th or 29th, though, so that’s not exactly a revelation. The bad news: forcing more turnovers after a year of forcing historically few turnovers is no guarantee of an improved defense. Of the sixteen teams in the sample (last year’s Trail Blazers left out, for obvious reasons), only 5 improved their defensive rank. The rest stood pat or got worse.
Granted, those teams all existed in their own contexts. That dot way over to the left is the 08-09 Pistons who radically remade their roster, changed coaches, and tanked. Nothing that extreme is happening to the Trail Blazers this year, so we can basically guarantee they won’t be jumping 23 spots in turnovers next year.
But this graph makes it clear that it’s not as simple as just forcing turnovers. Which makes sense. There is always a tradeoff. When you foul less, opponents aren’t as afraid to go to the rim. When you close out harder to contest jumpers, you risk a foul or two. And when you try to force more turnovers, you gamble and get out of position more.
Forcing turnovers, in particular, seems like something that would depend on personnel. It requires players who can take initiative and jump passing lanes, or who have the quick hands to create steals. On that front the Trail Blazers haven’t improved much. Wesley Matthews and Nic Batum can both pick off a pass once in a while, and LaMarcus Aldridge still has really, really quick hands. But there are still things that Terry Stotts can do. Send a trap once in a while, blitz a pick and roll, etc. At some point you get diminishing returns with that stuff, when the occasional turnover is outweighed by the compromise to your defensive system, but if the Trail Blazers are going to make the jump from a mediocre defense to a title-worthy one, it’s a compromise they have to make.