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Statsketball: What we've learned about Rajon Rondo through six games

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A little more than a week into the Rajon Rondo era, the Mavericks might be quietly forming a title contending team.

Mark J. Rebilas-USA TODAY Sports

Six games into the Rajon Rondo experiment may seem like a short amount of time to start taking stock of the Mavericks' newest big name acquisition, but there's a lot to take stock of, and there's a lot of new information, a lot of which seriously deserves attention. If you haven't noticed yet that this looks like a completely new team now, then you haven't been paying attention.

This team has been undergoing a pretty radical shift since its big new piece arrived, and it has given us, for all the apparent prematurity, some possible answers to some pretty salient early questions.

For one: I was the captain of the "you know, Rondo's defense just hasn't been very good," club, along with many others, and that, along with my regular subscription to the "Rondo has actually been hurting the Celtics' offense" organization, made me incredibly wary of this move. So: has Rondo actually helped the defense, and has the offense suffered in kind?

Luckily for Mavs fans, the early returns are encouraging. Let's take a look.

The defense

Defense was what Rondo was brought in for. For all the concerns about him harming the offense with his atrocious shooting, no amount of offensive damage would make much of a difference as long as Rondo could improve what was frighteningly close to a league-worst defense. If his defense was subpar, the offense would be a concern, but defense was always the calling card, here.

So: can Rondo still lock up guys from the point guard position? The answer appears to be an emphatic yes.

The signs that Rondo still had it in him -- for all the very real concerns in Boston -- were there before the trade. He was the league's 4th best point guard by DRPM, a measure that takes how a power impacts the floor without the influence of teammates; a particularly impressive feat by Rondo given that his backups Marcus Smart and, at times, Avery Bradley are also excellent defenders and likely absorbed some of what would otherwise be Rondo's "impact."

His DBPM -- a similar estimate from basketball-reference using boxscore data -- was also very positive, which is even more impressive for a position that largely doesn't get positive scores in that metric.

There were other reasons to be concerned. Heck, there are reasons to be concerned now: per nba.com's defense dashboard, opponents are shooting better than average when guarded by Rondo at literally every spot on the court, a problem that has largely persisted in Dallas as well as in Boston, with the exception of threes.

But the early returns are nonetheless clear; as of the last six games, the Mavericks have defended at the rate of 93.7 points per 100 possessions when Rondo is on the court, and a frightening 114.7 with him off. That's not a matter of Rondo largely sharing the court with Tyson Chandler, either. The Mavericks have actually defended better with Rondo on the court and with Tyson off. That 93.7 points allowed would lead the league by a large margin.

His strict on/off influence isn't the only thing that matters here, either. The best part has yet to come.

See, the crazy thing is, since the Rondo trade, the Mavericks have been defending at a rate of about 102.6 points allowed per 100 possessions, a rate which would be 3rd in the NBA, per Nylon Calculus' Pace Statistics, which are a mite more accurate than NBA.com's because they use real possession counts instead of estimates. Most importantly for the Rondo-led Mavs, this leap has been so drastic, and sustained long enough, that there is now a statistically significant difference between the Mavs' defense pre-trade, and the Mavericks' defense post-trade.

It's hard to know exactly how much better or worse Dallas got on defense, but I can say with 90 percent confidence (an actual precise number, here) that they won't defend any worse than 107.2 points allowed per 100 possessions and any better than 98.

Defense pre-and-post Rondo

So, at minimum, the Mavericks got two points per 100 possessions better on D. That's the difference, right now, between being a bottom 20 defense and being a top 15 one.

That said, if we can assume that the defense will continue to regress largely the same way the offense has in the beginning of the season (in a way that I predicted with 98 percent accuracy earlier this season, if you're curious, so I'm using that model again) we can predict roughly how Dallas' defense will regress from where it is to where it will settle.

Dallas' Defensive Rating with Rondo on the team should settle to about 104.8 points allowed per 100 possessions, a really solid mark that, if the league stays roughly stable for the rest of the season, would put Dallas squarely in the top 10 in defensive rating.

Projected League DRTG

This is huge for Dallas if it holds up (which is a big if; there's a big difference between a 104.8 defensive team and a 107.2). But everyone talks about how the big threshold for a real contender is something at least sniffing a top 10 defense.

Well, here it is, smacking Dallas in the face. Something damn near a top 10 defense. I mean, the most likely range for Dallas' defense right now is somewhere between 102.6 and 104.8. If that doesn't get you excited, I don't know what will.

The offense

The offensive returns have been not quite as hot, unfortunately, and as with the defense, there's no getting around Rondo's hand in the drop.

The Celtics have been worse with Rondo on the court for their last three seasons, including one when they were good. His lack of shooting and spacing and tendency to pass up open layups for flashy passes hurt, and for how fun he has been to watch, the same has been true here.

I know I've already been irritated watching him go to the whole from time to time, and given his shooting struggles, it's probably not the best idea to let him shoot second most of anyone on the team, above Dirk and Chandler Parsons.

The Mavericks have scored at a rate of 106 points per 100 possessions while Rondo's on the court and 106.9 points per 100 possessions with him off. That's not a huge decrease, to be sure, but those lineups without Rondo are largely Dallas' empty bench units heavily featuring Charlie Villanueva, Richard Jefferson, and Greg Smith. All of them are fine players to be sure, but if they, propped up with two of Devin Harris, Dirk, Parsons, or Tyson, produce a better offense than the 5-star lineup that Rondo mostly headlines, then that's somewhat damning.

Perhaps more damning overall, though, is the whole dip in offense that the Rondo trade seems to have caused. If the Mavs are only scoring 106 and 106.9 points per 100 possessions with or without Rondo, then what the hell happened to the 115.9 points per 100 possessions that they've been scoring for the season prior to the trade?

This graph on the Mavericks' sliding offense with Rondo on the court from the SBNation mothership initially seems dubious for the tiny sample size, but it turns out to be rather illustrative:

As with the defense, the drop in Dallas' offense has been statistically significant: this team is now officially, objectively worse on offense with Rondo. The confidence is more drastic, too. Unlike with the defense, where there's actually a 10 percent chance, roughly, that Dallas' defense is not any better with Rondo, I can say with 99.8 percent certainty that Dallas has gotten worse on offense.

But how much worse? Is it serious?

Well, maybe not. As with the defense it's hard to say exactly how much worse they got, but I can say with 90 percent confidence that this team will be scoring between 112.2 points per 100 possessions and 104 by the end of the season.

Offense Pre and Post Rondo

Also as with the defense, I can project how the Mavericks are likely to regress as the season goes on, and funnily enough, they end up with an offense roughly like the one they've had since Rondo came back: 108.1 points per 100 possessions.

That's worrying. That's a huge drop from Dallas' 115.9 mark they have right now for the season. On the other hand, there are several serious causes for optimism here. First: that ORTG would still rank somewhere really close to the top 10 in the league right now, another baseline that people like to use for "title contention." All they have to do is be a little better than the math expects (which isn't even that hard!) and they crack the top 10.

Projected top 10 offense

But more importantly, Dirk has been -- his monster game against Oklahoma City excepted -- really off of his game for a long while now, and if we can keep assuming that he'll get it together, all of these offensive concerns will assuredly ramp back up to somewhere much closer or above its max. When Dirk's hitting, the rest of the offense just moves that much better.

It's hard to say how this offense actually ends up looking, exactly, but it's a downgrade. That's probably fine, all things considered, but maybe a bit worrying, too.

The overall picture

If Dallas ends up finishing the season roughly how they look like they will right now, they're expected to end up with a point differential of about 5.2 points per 100 possessions. It's telling how far the offense has fallen that that's a large drop from Dallas' current 7.4. Given that Dallas was never quite as good as it's point differential (thanks to the Mavs crapping on bad teams) that would be the difference between somewhere around 58 and 55 wins, approximately.

A drop from 58 wins to 55 because of a declining offense isn't the worst thing in the world, provided that the defense is skyrocketing from bottom of the league to maybe top 10.

Dallas isn't getting dropped out of the playoffs with a win total like that, and a few extra wins from what they're currently on pace for isn't likely to get them anymore seeds either. They're likely to stay between 6-8 largely independent of the trade, so seeding consequences aren't large.

And, I mean, if Dallas can get to the top 10 in defense, as long as the offense is at least "pretty good" with the versatile weapons that Dallas has, that's a better outcome headed into the playoffs than the alternative. Defense, and being great defensively, is exponentially more important to success than offense, and a team with a top 15 offense and a top 10 defense is much harder to exploit in the playoffs then one with a historic offense and horrible defense.

Consider this scatter plot of all the team's offenses and defenses:

Offense/Defense Scatter

There are some teams not in that bubble who are probably contenders -- Toronto and Cleveland, with elite offenses and mediocre defense come to mind -- but there's a distinct set of teams floating up with a high defense and decent offense, and Dallas fits right in on the low end of that group. They're longshots, but with Rondo on the squad they also look like a serious team with serious intentions.

Besides, all those concerns are mostly this team's expected end, but there's a ton of variance right now, and the Mavs went out and got Rondo for the chance that he could launch the team to contention. To that end, if everything goes right, and Dallas ends up with a defense of around 102 points allowed and an offense around 112 points scored...that's not just a title contending team, that's a borderline title favorite, and that's not even wildly out of the question.

For all that optimism though, it's important to temper expectations. As was before this trade, this team looks more or less like it's going to top out at "really, really good."

Still, the goal of getting Rondo was to potentially raise this team's ceiling. Well, consider the ceiling raised. We've had tantalizing glimpses of what this team can be. Now it's time to see if the team can actually get there.