Stephon Castle is having himself a season. He has followed up his Rookie of the Year with improvements to every aspect of this game. Averaging 16.5 points, 5.1 rebounds, and 7.1 assists sounds great, but for a player like Castle, it just doesn’t tell the whole story.
Currently, he doesn’t shoot particularly well, averaging a below-average 51.1 percent effective field goal percentage. That isn’t great, but he’s still one of the most effective players on the court. He brings a number of intangible qualities
that don’t quite make it in the box score but do make their effect felt in the win column.
Diving a little deeper, is there a way to quantify more of what Castle brings night after night? Yes. The advanced stats start to shed more light on the Spurs and Castle’s success in a more tangible way.
Plus/minus stats are the first place to look. How does the team do with him on the court versus off? Overall, it’s not a great metric because the data carries so much noise and outliers (such as who he shares the court with) and can be misleading in any particular game, but it’s not a bad place to start when looking at a large sample size. Castle’s raw plus/minus is +5.5. Not bad at all.
Second is his defense. Castle is one of the best point-of-attack defenders out there and a genuine pest to any ball handler in the NBA. Looking at opponent points per 100 possessions, it drops 4.7 points with Castle on the floor, per cleaningtheglass.com. That isn’t all attributable to Castle, but it is notable. It would be surprising if Castle isn’t on an All-Defense team.
Next up is offense, beginning with transition, where the Spurs have been very efficient this season. Per Cleaning the Glass, they are first in points per 100 possessions off live rebounds (+1.9) and 6th in overall points per 100 (+3.4). Where Castle comes in is how often the team is able to get into transition play when on the floor. That transition frequency goes up 2.3 percent (93rd percentile) overall, and 6.3 percent off of live rebounds (97th percentile) with Castle in the game. In short, the team gets rebounds and goes with Castle on the floor.
What about getting to the rim? His shooting may not be there yet, but he gets to the basket. 43 percent of his shots are at the rim (93rd percentile among combo guards). Not only this, Castle is getting fouled on a whopping 20.5 percent of his shots. He isn’t shooting particularly well, but if one out of every five of those shots gets him to the free-throw line, where he shoots 74 percent, he’s making up for it.
Looking at a more sophisticated all-in-one metric, one that tries to pare down the noise to a player’s actual contributions, there is Estimated Plus-Minus from Dunksandthrees.com. He’s at +2.8. For context, that’s 93rd percentile league-wide. Overall, a pretty remarkable figure for a player who is only 21 years old and only going to get better.
All of this is to say that Castle is a winning player. He isn’t out for his own stats and finds ways to impact the game, no matter what that looks like. Now, as this young team enters its first postseason, we’ll see if Castle can keep it up, if not find another gear.
