The idea of a “ -stopper” goes back quite aways. Ruben Patterson characterized himself as a Kobe-stopper, but even before that players like Byron Russell made a name for themselves primarily because of their ability to defend a single player (Michael Jordan in Russell’s case). In the past, actually assessing these claims with statistics required tracking things by hand or using anecdotal data like Jordan’s field goal percentage against the Jazz, not necessarily focusing in on specific possessions where Russell was guarding him.
With the release of the NBA’s new matchup box score data, backed by Second Spectrum’s data tools, we can hone in a bit more specifically on offensive-defensive player matchups. The defensive matchups are assigned based on an algorithm that estimates which player the defender was guarding for the majority of a defensive possession. So if Russell had been guarding Jordan for the majority of a possession but was screened off at the last second for Jordan to sink a jumper over a rotating Karl Malone, Russell would still receive credit as the defender.
This can lead to some scenarios where a defensive player is being credited (or debited) for one of their teammates actually contesting a shot at the end of a possession, but this “majority of the possession” approach is probably a better proxy for defensive responsibility than just assigning it to whichever defender was closest at the time of the shot (which is the case for the defended and contested field goal stats that have been available on the NBA’s website for the past few years).
Nylon’s Positive Residual has already done some work on finding patterns in height advantages in this matchup data but I thought it would be fun to take the data and slice it down to who has been the most effective at guarding a few prolific scorers.
LeBron James has won just a single scoring title, in 2007-08, but he is a uniquely difficult defensive matchup. Between his strength, size, speed and offensive versatility there are few players who would seem to demand such a specialized defender to slow them down. We only have this matchup data available for this season, which means some small sample size issues, but we can at least see a few patterns.
The table below shows the players who have spent the most total possessions matched up with LeBron this season.
Obviously, this list is heavily influenced by the number of matchups — the Hawks and Pacers are one of three teams that the Cavaliers have already played four times this season. But you also get a sense of the kind of archetypes teams typically use on LeBron. Giannis is the only player with significant size advantage but generally teams are looking to match one of their biggest, strongest wing players with LeBron.
As you would expect, the players have had varying degrees of success in slowing down LeBron. The graph below shows every defensive player who has been matched up with LeBron this season, charted by the total number of possessions they’ve spent on him and the points per possession average of LeBron when they were guarding him. I’ve included the list above and highlighted a few other notable players.
We don’t often look at a player’s individual points scored per possession played so the scale could probably use some context. LeBron is averaging 35.2 points per 100 possessions this season, or 0.352 points per possession played. Anything below that would represent a defender holding him below his average scoring rate for the season.
Of the players highlighted, Paul Zipser and Ben Simmons are the defenders who have been victimized most often by LeBron, the scorer. But most of the group I’ve highlighted here, including Dillon Brooks, Wes Matthews, Jimmy Butler, Courtney Lee and Stanley Johnson, have held LeBron below his season-long average scoring rate when they were the primary defenders. The mass of plots towards the upper left of the graph may be a representation of LeBron’s ability to exploit mismatches, he has scored at a rate of 0.43 points per possession against players who have spent less than ten total possessions as his primary defender this season.
Of course, slowing down LeBron as a scorer is just one piece of defending him well. LeBron is also an exceptional passer, currently ranking second in the NBA in potential assists per game. We can also factor in his assists and the implied impact of his offensive gravity and chart the same defensive players by the rate at which the Cavaliers scored per possession when they were the primary defender on LeBron.
The Cavaliers have scored an average of 111.4 points per 100 possessions with LeBron on the floor this season, so anything below 1.11 in the graph above would be a defender helping hold the Cavaliers below their season-long average when that player was matched up with LeBron. A few of the players from above still look effective in this context — Dillon Brooks and Jimmy Butler. Wesley Matthews looks a lot less effective. Kevin Durant pops up as an impressive option as does Kyle Anderson of the Spurs.
Interestingly, Courtney Lee and Dillon Brooks also pop out as effective defenders when matched up with James Harden and the Rockets (the scale here is adjusted because Harden had so many possessions where the average points per possession was above 2.0).
Lee caught some traction in trade rumors around the deadline but the Knicks ultimately decided to hang onto him. His Defensive Real Plus-Minus is below average this season (-0.79) but perhaps that has been dragged down in general by the context of the Knicks. If he really is able to rise to the challenge in these key matchups, he could be a very valuable addition for someone this summer.
Brooks is also interesting, with a Defensive Real Plus-Minus just below the league average at (-0.24). As a rookie that mark is fairly impressive, especially considering his reputation coming into the league was mostly as a scorer. He’s struggled on offense quite a bit this season but if he can develop into an above average defender he could provide a lot of value for the Grizzlies over the next few years.
Kevin Durant is much bigger than Harden and plays up the positional scale a bit more than LeBron, so we see some different defenders on his chart.
Paul George has been exceptionally effective defending Durant, although Durant was dinged up for one of their games this season which could have impacted these numbers. Brandon Ingram doesn’t have a strong defensive reputation but, especially as a 20-year-old, it’s impressive to see him somewhat holding his own against one of the best scorers in NBA history.
Obviously there is a lot more nuance to be added to this data. In most cases I’ve only highlighted players with at least 50 possessions in the defensive matchup but even that is a fairly small number. If the NBA does eventually go in and backfill data from previous seasons using Second Spectrum’s algorithms, it would be great to compare this data across seasons and team changes to try and isolate the true effect of each individual defender. Obviously, what we have isn’t perfect but let’s not let perfect be the enemy of good.