Notes on GM Survey: Is Rondo in Danger of Being Overrated?
Posted by Zach Lowe on Oct 7, 2009
As you probably saw, the NBA released its annual survey of the 30 GMs. The most interesting Celtics-related revelation for me involved the fast-rising status of our young point guard, particularly his reputation as an elite defensive player.
• Rondo was one of just seven players to receive a vote for best overall defensive player. (KG tied for second)
• Rondo finished fourth (with 6.9 percent of the votes) in the poll for best perimeter defender. Only Kobe Bryant (the undeserved winner), Shane Battier and Ron Artest received more votes. (Note: Two non-Celtics GMs voted for Rondo here).
• Rondo tied with Kobe Bryant with an even 25 percent of the votes atop the voting for best on-the-ball defender (and ahead of Artest and Battier!)
My question: Has Rondo really progressed to the point that he should be considered one of the 10 best overall defensive players? Frankly, this seemed at first glance premature. Rondo is undoubtedly a good defensive player. He’s long, smart and annoying as hell on the ball. But he’s also a gambler, and we’ve seen him compromise our defensive structure going for those reach-around steals. (Side note: We’ve got to come up with another name for this play. Reacharound is too…well, we all know). My naked-eye impression is that he is overrated as a screen/roll defender.
Of course, ranking players based on their defense is fraught with problems. The NBA is a team game, and different teams use different schemes. Some switch on screen-rolls; some don’t. Some help more aggressively than others. Trying to evaluate a single player outside of his team defensive scheme is a little like ripping a few pages out of a book and judging the author based on those pages.
That said, there are some metrics that at least attempt to measure a player’s defensive ability. I checked them all to see if Rajon really does deserve to be mentioned among the league’s elite defenders.
And you know what? We might be that point with him already.
We’ve got traditional stats, and Rondo does very well there. He averaged 1.86 steals per game last season, 5th in the league, and his 0.77 steals-to-fouls ratio—which sort of measures how effective players are at stealing the ball without fouling—ranked 7th overall, according to ESPN.
Good stuff, but there are more “advanced” stats to look at.
Let’s start simple, with 82games. Last season, the Celtics defense gave up 103.4 points per 100 possessions with Rondo on the court and 103.2 with him on the bench—almost exactly equal. But that doesn’t tell us much, does it? Rondo played 66 percent of the team’s total minutes and an even higher percentage of the team’s meaningful minutes (i.e. non-blowout minutes). So it’s not surprising that the gap in points/100 possessions here isn’t huge. (Though it should be noted it was huge on offense—the team scored 6.5 more points/100 possessions with Rajon on the floor).
Also on 82games: Rondo’s direct counterparts at PG recorded a 16.5 PER. That’s above the league average of 15.0, suggesting Rondo didn’t do that great a job as a head-to-head defender.
Ah, but there are problems here, too, right? Rondo defends a lot of elite point guards, so perhaps holding them to a 16.5 PER is actually pretty good.
So let’s turn to Basketball Prospectus, which just developed a new set of defensive stats. Here are Rondo’s:
Don’t be overwhelmed by the numbers and the NASA-like abbreviations. If you want the definition of each category, go here. For now, focus on dMULT, that category just to the right of center. That number (0.918) measures how well the point guards Rondo defended performed against the Celtics as compared to their performance against the rest of the league. Example: If point guards on average did just as well against Boston as they did against every other team, the number in that column would be 1.00—or 100 percent, if you move the decimal over two spots.
So that .918 mark means Rondo held opposing PGs to 91.8 percent of their expected productivity. And that is a HUGE, HUGE difference. Battier, for instance, held his direct counterparts to about 95.5 percent of their expected production, according to Basketball Prospectus, and that figure (.955) is also excellent.
Also, that number just to the right of dMULT—the 1.144 number under the column dQUAL—is the average of the overall season-long production of every player Rondo guarded. In other words, combine all the opposing PGs Rajon defended and create an imaginary player that represents the average of all those enemy PGs. This number—this 1.144 thing—would measure how good that player would be compared to an average NBA point guard. If Rondo’s head-to-head counterparts were exactly average, that number would be 1.00.
But it’s 1.144, which means those players performed 14 percent better than an average NBA point guard over the course of the 2009 season! That’s huge! Check out Battier’s numbers here again—his counterparts, the best of the best among small forwards and big shooting guards, scored 1.056 on this scale. At least according to this scale, Rondo is guarding better players overall than Battier is.
Long story short: Rondo appears to be a pretty damn good defender under BP’s metrics. But let’s try one more place: Basketball Value, which uses an adjusted plus/minus formula to (and I’m simplifying here) tease out how an individual player would rate when surrounded by average teammates and opponents.
And here, Rondo rated as the best Celtic for the 2009 season.
So maybe my initial impressions were unfair, and maybe these 30 NBA GMs were right: Rajon Rondo, right now, appears to be an elite defensive player. Maybe this is why these guys are GMs and I’m a blogger.