2015 WNBA draft prospects: What is UConn center Kiah Stokes' pro potential?

One of the more interesting questions for me before last night's NCAA women's national championship game was how the Notre Dame Fighting Irish would attempt to defend the Connecticut Huskies, who had once again looked dominant for the majority of the season.

Part of the answer was somewhat simple, for anyone who recognizes that defending UConn is mostly about harm reduction: whoever was guarding Kiah Stokes left her to double someone elsewhere.

And they didn't just leave her: the Notre Dame defense entirely ignored her when she wasn't in pick and rolls, which meant she had to float to the perimeter away from the ball to avoid clogging up the entire offense.

I probably wouldn't have spent much time focusing on that were it not for the fact that Stokes has not only been bandied about as a WNBA draft prospect but a first round prospect. In what was an extremely weak draft for centers prior to Amanda Zahui B. declaring herself eligible, that's not exactly surprising. But Notre Dame's defense of her last night reflected the statistical red flag that has been on my mind all season: how much can a player that is left unguarded against college defenses be expected to contribute on the professional level?

The Invisible Woman

Statistically, what we saw from Stokes last night -- and for much of the season -- was a reflection of her extremely low usage rate of 11.88% during her senior season; men's college basketball analyst Ken Pomeroy has labeled any player with a usage rate under 12% as "nearly invisible", which would probably be a fitting tag for what Stokes was on offense last night (or at least the way Notre Dame treated her). And you don't have to look much further than how defenses treat Stokes to understand what usage rate is measuring: it's the percentage of offensive plays in which a player was involved in the outcome (field goal, free throw, or turnover). In that players consistently not recording scoring attempts or turnovers are likely not focal points of their offenses, it can be seen as a proxy for either aggression or involvement in a team's offensive scheme.

However, simply dismissing Stokes as "nearly invisible" in college is not quite sufficient to understand her value as a draft prospect: the more important question is whether a center prospect's usage rate really matters, which is something that I've never actually considered for an easily defensible reason.

If you look back through the last decade of center prospects drafted, nobody has had a senior season usage rate of less than 13% (Marita Payne, 2006) -- in other words, if Stokes is drafted (as expected), it would be the lowest usage rate of any center drafted in the last decade. In fact, as far as I know (many women's college statistics are hard to track down or incomplete), that would actually be the lowest usage rate of any player drafted since 2005 at the very least. And if you take a step further and look at Stokes' minutes (a factor in the usage formula), no center has made a roster after playing less than 20 minutes per game in their senior season.

This is something that we've already discussed in the past for point guards and wings: the low-usage college point guard prospect has pretty much gone extinct in the WNBA; low-usage wings haven't really had a hey-day anytime in the recent past. And by low usage for those positions, I mean the 20% mark, which is the threshold for what Pomeroy calls a "significant contributor" in his five-level scale — Stokes is clearly far beneath even that.

The reason for low usage players not making often is somewhat related to another observation Pomeroy has made about year-to-year changes in usage rates among college players: "...role players don't usually become go-to guys from one year to the next, or at any point during their careers...By and large, a player's role on his team in one season is a good indicator of his role the following season." As one might assume, that holds even more true for the transition from college to pro: college players, especially centers, very rarely exceed their college usage rates in the pros and it's far more likely that they'll drop. While pro scouts might not explicitly think about usage rates when evaluating players ("Wow - that player's 17.77% usage rate will probably decline in the professional ranks so maybe we should cut her."), it's far more likely that more dynamic offensive players simply offer more to a team, which could lead to them not only getting drafted but also standing out more in training camp.

Does usage rate even matter for center prospects?

So since we don't even have any sort of reasonable comparison for Stokes because no nearly invisible center prospect has been drafted before, how are we supposed to interpret her potential?

What about the next level up, where Auburn's Marita Payne sits? Nope — Payne, as it turns out, is the only "limited role player" (12%-16% usage rate) drafted in the last decade. It's not until you reach the "role player" level that you find a real group of players drafted who actually played significant minutes in the league.

NCAA centers drafted from 2005-2014.

So now it might be clear why I haven't mentioned the usage rates of center prospects much in the past: this group is a total mixed bag, ranging from All-Star to training camp cut. There isn't the clear cut off point that exists for point guards or wings, positions where ending plays is a logical end point from where and how they play; for centers, role player centers can end up making rosters and having relatively successful careers while high-usage "significant contributors" (24%+) can get cut or take a few years to find their place.

Nevertheless, if we really wanted to draw conclusions about this modest group of 10 centers, the outlook is a whole lot more optimistic than that of other statistical thresholds (which is highly relevant to one of Stokes' UConn teammates in this year's draft...and we'll tackle that later). We can imagine a number of scenarios where a low usage center makes it despite having a limited role in their team's offense: just looking at the list above: centers can be useful in anchoring a defense, passing, rebounding or setting screens — things that aren't reflected in usage rates.

And Stokes possesses a couple of noteworthy strengths.

Increasing visibility

You'll note that Stokes' true shooting percentage (TS%) is significantly higher than that of the other sub-20% centers listed above. That she crossed the 60% threshold is quite significant because just nine drafted players* (two in 2014) have crossed that threshold in the last decade, including Tina Charles (2010), Sylvia Fowles (2008) and Brittney Griner (2013). In short, although Stokes is at the bottom of the list in usage rate, she's actually right behind Fowles in 10th in shooting efficiency. If you're thinking shooting efficiency doesn't matter much when you're not really shooting much and certainly not expected to take many contested shots...touche. So let's move on.

The other thing that really stands out about Stokes is her passing efficiency. 32 assists to 31 turnovers isn't much, but a pure point rating of -1.37 is quite good among centers; her assist ratio (the percentage of touches that result in assists) of 15.48% is actually one of the top five among centers in the last decade, up there with the likes of outstanding post passers like Stanford's Jayne Appel (2010) and Stefanie Dolson (2014). But even that comes with a caveat: by virtue of handling the ball and playing more often, both Appel (93) and Dolson (113) had around 3-4 times as many assists as Stokes. Again, what does efficiency matter if you're not taking that many chances?

Stokes is also a solid offensive rebounder (12.89% offensive rebounding rate), but at this point I can imagine the argument that has already been made coming up: STATS DON'T MEASURE HEART/IQ/DEFENSE/WORK ETHIC/SKILL/TRUE IMPACT/WINNING/GENERALIZED AWESOMENESS! And that's true. But that was also the line of reasoning in support of Kelly Faris, who also had a senior-season usage rate so low for a wing that it defied any reasonable comparison (15.97%, which was up from 13.85% in her junior year, according to WBB State): those stupid numeric symbols on paper don't measure her true value! The problem is that if we can begin by agreeing that pro defenses are better than college defenses, then it's really hard to make a case that someone will suddenly blossom into a more dynamic offensive player as a pro than they ever showed in college without considerable time — that is definitionally a "project", which is not a bad thing but requires some patience that WNBA teams don't normally exercise.

Part of what it all boils down to for Stokes (and Faris?) is that part of what makes UConn coach Geno Auriemma great is that he gets the most out of his players. More often than not — and I can certainly think of exceptions — what we see from Auriemma players in their senior year is approximately what we're going to see a pro coach get out of them, accounting for all the expected rapid adjustment growing pains.

Ultimately though, both Stokes' draft position and roster status come opening day will be interesting to watch because we haven't seen a player like her enter the modern pro game at all.

*Corrected: This previously read that there were five centers with true shooting percentages over 60% and that Stokes was the sixth. It should have read that there are nine centers from major conferences drafted in the past decade with TS% of > 60% with Stokes potentially being the 10th.