The alien's right-hand man: How Stephon Castle is turning into the perfect Wembanyama sidekick

Everything the Spurs have done in the last 18-ish months has revolved around maximizing Victor Wembanyama’s prime. How to maximize that prime, however, isn’t always as clear-cut.

What skills would you desire next to someone like Wembanyama?

You’d want a perimeter defensive menace, someone who can funnel ballhandlers into Wemby’s waiting arms. Someone who can play on or off the ball, because sometimes Wembanyama needs to be fed, and sometimes he needs to do the feeding. Someone who can take some late-game pressure off of the big man. Versatility, particularly on offense, is critical. If you don’t know what kind of monster Wembanyama ultimately becomes, you need someone who can grow right along with him, who can adapt to his evolution.

Well, give the Spurs front office some credit. It hasn’t taken long for rookie Stephon Castle to check almost all those boxes and become the second-most-important player strolling the River Walk.

Since being thrust into a starting role after Jeremy Sochan was injured, Castle has been a revelation. Let’s get the surface-level stuff out of the way. In his first seven games, all off the bench, he averaged 6.0 points, 2.6 rebounds, and 2.3 assists while shooting 31% from the field and 2-for-16 from deep in 19.9 minutes per game. But in his last 10 games, all starts, he’s averaging 14.3 points, 2.7 rebounds, and 4.5 assists while shooting 43% from the field and 16-for-48 from deep in 30.3 minutes per game. That’s a massive improvement.

The Spurs started 3-4 (against a very difficult schedule, it must be noted), but they’ve been 6-4 (including a win over OKC without Wembanyama) since Castle entered the starting lineup for Sochan.

Castle is unusually flexible for a rookie guard, seamlessly shifting between spot-up, cutting, and on-ball roles. His size (over 6’5” pre-shoes and pre-hair, 210 pounds of gravel and sinew) is a huge advantage. More than a third of his shots occur after he muscles his way to the rim, and he’s hit an excellent 70% of rack attacks since he became a starter (a good number for any guard but an outrageous one for a rook).

But those are just numbers. There are few players so far this season with a bigger disconnect between the raw stats and what the eye test says, and my peepers won’t shut up about Castle.

The dunks are fierce; the dunks are fire. Castle’s preferred slam package pays homage to early Derrick Rose with powerful two-handed tomahawks:

But where the dunks are loud, Castle’s most underrated skill is quieter. As the season has gone on, coach Mitch Johnson (filling in for the recovering Gregg Popovich) has put Castle into action as the roll-man more often. He’s learning how to exploit the attention gravity that Wembanyama emanates, leading to some gorgeous plays:

Castle has an innate feel for when to lay the wood and when to slip. Look how effectively he sells the screen before ghosting to the rim for an easy layup:

Pair that screening and slashing with strong transition play and some ballhandling creation in the pick-and-roll, and yeah, the scoring has been better than expected from a rookie guard.

Castle is a point guard at heart, though, and he has been good enough running the position that Johnson chose to close their most recent game with Castle instead of Chris Paul. While the rookie certainly isn’t on the Point God’s level as a passer, he’s behind only Washington’s Bub Carrington in assists per game for rookies. As he gets more comfortable, we’ll see more of his latent creativity bubble to the surface:

But the most eye-opening part of Castle’s offensive performance so far has been his willingness to launch from deep — and I do mean deep:

Note the score and time of that clip. That’s a rookie who was branded a non-shooter coming out of college calmly stepping into a nigh-30-foot bomb in the closing minutes of a tie game against the Warriors.

No, Castle isn’t a dead-eye sniper right now. That’s okay; I’m far more impressed with the volume — 7.0 triples per 100 possessions is on the low end of average for an NBA guard, but it’s far more than I would have expected before the season began. Castle hasn’t been shy, and he’s taken open looks when defenses give them up. Sometimes, as in the clip above, he creates his own looks.

That chutzpah is an important ingredient for anyone who wants to be next to Wemby for the long run. Think prime Khris Middleton next to Giannis; think early-days Kobe next to Shaq. Every great big man needs a ballhandler who isn’t afraid to punish overloaded defenses, who can both fend for themselves and elevate the greater whole. It’s early days still, but the mindset is right.

If the shooting confidence has been a pleasant surprise, the unexpected aperitif, then the rabid defense, his meat and potatoes, has lived up to the billing. Castle is a dawg. Any group with Wembanyama will be devastating basket-guarders, but here’s something fun: Wemby-less lineups with Castle still rank above-average defensively (the Spurs are a dumpster fire with both players off the court).

Castle is already an elite screen navigator, an important skill for Spurs perimeter defenders to have with Wemby lurking on the back line. Even on the rare occasions he does get beat off the dribble, Castle stays in the game. He provides outsized rim help for a guard, looking like a miniature Roy Hibbert bringing verticality back into the basketball lexicon:

Castle has lightning lateral quickness and a bloodthirsty attitude. He loves picking guys up full-court to keep the heat on, for better or worse. Sometimes, yes, he’s burned on his backheels by Scoot Henderson:

(That wouldn’t have been a problem with Wembanyama on the backline instead of Zach Collins.)

But sometimes, he sucks all the oxygen out of Steph Curry’s lungs:

It would be a shock if Castle doesn’t make an All-Defensive team at some point in his career.

For the Spurs, the rookie’s been about as good as could be expected in most respects and better in some. However, his early success puts them in an interesting position. The team’s recent starting lineup of Wembanyama, Julian Champagnie (long a Poetry favorite!), Paul, Castle, and Harrison Barnes has been the second-best in the league in this young season (behind only a Sacramento fivesome who, in a tiny sample, have put together the most spectacular offense since Alexander the Great). However, that leaves out two injured players expected to be key parts of the team’s future: Devin Vassell and Jeremy Sochan.

Vassell is a proven high-volume shooter and scorer, while Sochan had a blistering start to the season (although his own success may have come at the expense of the team’s — that’s another story entirely, one heavily tied to the vagaries of Wembanyama’s shotmaking). Both are young in their own right; Vassell just got a big payday, Sochan’s angling for one in the near future. Choosing to keep either or both on the bench behind Castle (or Champagnie) is difficult for many reasons.

I’m unsure which direction the Spurs will go when Vassell and Sochan fully heal. I’d bet on Castle returning to a high-minutes bench role (though it’s not what I would do), with the expectation that he takes Chris Paul’s starting spot next year. Right now, though, he has at least a little more runway to make his case to stick in the starting lineup this year for good.

The Spurs are already solid and may well finish the year at or above .500. In a turgid Western Conference, though, there’s no guarantee that record even earns a play-in berth — which is totally fine! One more year grabbing rookies from a stacked draft class before Wembanyama (and Castle) are too good to be denied is hardly a bad thing. The Spurs could benefit from a bit more talent acquisition; they’re still figuring out how to put the best people around Wembanyama, and Barnes and Paul won’t be around when this team is really good. But regardless of whether he plays 30 minutes per game as a starter or 25 as a backup, Castle has proven that he’s ready to thrive next to the extraterrestrial in the middle.