2015 WNBA Draft prospects: Duke's Elizabeth Williams & low efficiency post prospects

For those of us that are not medical professionals or haven't stayed at a Holiday Inn recently, medical risks are among the most difficult things to anticipate when trying to figure out a professional prospect's potential.

Unfortunately, the 2015 WNBA season will be affected by them in more ways than one with the post position being particularly affected.

Texas' Nneka Enemkpali had a season-ending knee injury during conference play that will likely put her at a disadvantage in starting her WNBA career as an undersized post player despite being an impressive rebounder. Tennessee's Isabelle Harrison had injury issues throughout the 2014-15 NCAA season, culminating in a season-ending knee injury. Looking ahead to the actual 2015 season, 2014 first round pick Natalie Achonwa will begin her career after also suffering a knee injury during the 2014 NCAA Tournament.

Last season, both Achonwa and Gray were drafted in the first round despite their injury concerns with general managers choosing to invest in the future based on potential demonstrated in the past. It's not entirely clear whether Enemkpali and Harrison will pull that off this season, but in a weak draft with teams possibly looking to defer the cost of adding players someone is likely to gamble on the future instead of looking for immediate help at some point in the draft. The challenge for those two, as we'll discuss below, is that they both have red flags that might've limited their potential regardless of their injury status.

And none of that is to mention the guards lost to injury in consecutive seasons now: Achonwa will be joined in her deferred rookie status by Duke point guard Chelsea Gray, who hasn't played a whole season of basketball since the 2011-12 NCAA season due to consecutive knee injuries. 2015 senior Rachel Banham suffered a season-ending injury in time to redshirt and will enter the 2016 WNBA Draft after having a chance to prove herself again.

But the even harder thing to assess is the risk of a player who has an injury history that they've seemingly overcome.

Duke's Elizabeth Williams has had a couple of lower extremity injuries that haven't actually cost her many games, but seem to loom larger than missed games in the minds of observers as I've talked to people throughout the year: an ankle injury suffered early this season cost her two games and seemed to linger while a stress fracture in the 2012-13 season did in fact cost her games and linger. On their own, they're not a big deal, but when you think about the history of bigs with leg problems in professional basketball it's surely not going to go unnoticed.

Putting those aside though, you still have a player who has considerable talent paired with some concerns.

Her defensive value, while generally immeasurable, is captured well by having one of the best block percentages in the nation (6.9%) while managing to stay out of foul trouble better than it might seem: her personal foul efficiency (BLK + STL / PF) is among the top five among centers in the last 10 years (2.04). However, the fact that she's a relatively poor defensive rebounder (15.2%) compared to other center prospects stands out as a bit of concern about her ability to control the paint at the next level.

Conversely, her offensive rebounding rate of 13.56% is outstanding for a NCAA center and gives her a very clear strength that she can build upon at the next level: offensive rebounding tends to translate well to the WNBA. That alone certainly adds to the idea that the 6-foot-3 post might be better suited to the WNBA's power forward position (where most offensive rebounders usually end up) as opposed to a center position that is only getting bigger and more physical by the year. Even that strength offensively ends up pointing directly to one of Williams' biggest weaknesses and concerns for her transition to the pros: her scoring efficiency.

According to Synergy Sports, Williams got the majority of her scoring opportunities (38.4%) off post-ups. The problem has been that she hasn't been particularly adept at scoring off those opportunities: in her junior season, Williams placed in just the 50th percentile in the entire nation on post-up plays (.786 points per possession); in her senior season, that number increased to the 58th percentile at the end of conference play (.797 PPP) but is still far beneath what you'd hope for in an elite WNBA post prospect.

That problem is compounded by the fact that she really doesn't have much of a face up game: according to Synergy (which sometimes has quirks in how it counts possessions), she had just 38 spot up possessions in the last two seasons. And in a WNBA era where the best of the best (e.g. the Phoenix Mercury) are making heavy use of the pick and roll, the fact that Williams had just four pick and roll possessions in her senior season doesn't necessarily raise confidence in her pro readiness.

Williams has to be looked at as a potentially solid defensive presence in post at the next level, but her offensive profile is rather alarming for someone who has spent much of the season — and her collegiate career? — being considered a lottery pick. And that combination of a mediocre offensive repertoire (for a pro prospect in 2015) and extremely low efficiency is a major red flag for Williams' pro potential.

Centers

Scoring efficiency (true shooting percentage): Of the 50+ drafted NCAA centers from 2005-2014, there did seem to be a pretty clear distinction between the shooting efficiencies of successful and unsuccessful draftees: unsuccessful ones were almost by rule under 55% (there are two exceptions: Chante Black (2009), who became a strong rebounder in the WNBA, and Krystal Thomas, who had a TS% of 50%). The 55%-60% range - which includes Stanford's Jayne Appel (2010), Minnesota's Janel McCarville (2005), Rutgers' Kia Vaughn (2009) among others - is a bit more of a mixed bag.

Williams finished her senior season with a true shooting percentage of just 51.9%, which puts her in the bottom five among true post-up centers drafted since 2005 (meaning, LSU's Theresa Plaisance is excluded because of she was mostly a face-up center who was more of a stretch five for Tulsa in her rookie year). The fact that Williams doesn't make much of that up at the free throw line (a FTM/FTA ratio of 22.85%) is even more reason to wonder how much value she could have offensively.

And if she'd struggle that much against college competition, it's reasonable to wonder what kind of impact she'd have in the pros.

Notable past examples: Nikki Greene (2013), Chanel Mokango (2010); Jacinta Monroe (2010); Anna Prins (2013), Waltiea Rolle (2013)

Examples from this season's senior class: Elizabeth Williams, Duke; Isabelle Harrison, Tennessee

Personal foul efficiency (stl+blk/pf): This is an interesting one that isn't a strict rule, but players that fall under the successful centers' average of 1.05 (think of that as a steal and block per personal foul) have struggled initially in the league, although a few maintained roster spots and players like Jayne Appel and Kelsey Bone stand out as major exceptions. And with those exceptions noted, this one is probably more of a "yellow" caution flag than a red warning flag.

Notable past examples: Quanitra Hollingsworth (2009), Olayinka Sanni (2008), Nikki Greene (2013), Anna Prins (2013), Tye'sha Fluker (2006)

Examples from this year's senior class: Elem Ibiam, South Carolina

A low pure point rating: This is definitely more yellow than red. A low PPR doesn't make or break a prospect's chances of making a WNBA roster - even in the 11-player roster era - but it does suggest that a player might struggle at the very least. PPRs under -6.00 are generally a red flag for post players, with one major exception: Sylvia Fowles (2008). But Fowles' example is where this one gets more interesting.

Fowles' 54 steals in her senior season are the second most steals of any since the 2008 draft (Laura Harper edged her for the most at 55). But every other player with a PPR even less than -5.00 really struggles — most of the players you could consider being "exceptions" have ended up being limited-minute reserves (e.g. Kayla Alexander, 2013; Sasha Goodlett, 2011; Quanitra Hollingsworth, 2009). Kia Vaughn was the player with a PPR under 5 who has succeeded, but even she struggled out of the gate.

Notable past examples: Asya Bussie (2014), Nikki Green (2013), Kelly Cain (2012)

Examples from this year's senior class: Elem Ibiam, South Carolina

Power forwards

Post players 6'1" and under: This is one of those red flags that I hate to list because it seems so unfair, but the track record for post players (listed) at 6-foot-1 and under is just really poor in terms of making rosters in the year immediately following their draft selection and/or sticking on rosters; the exceptions to that rule were stunningly efficient scorers.

And the results are reflected in the fact that teams haven't really even been drafting them lately. But this year, in a draft that is widely considered "weak", there are likely to be a couple drafted who will have the opportunity to buck patterns of the past.

Notable past examples: Alysha Clark (2010), Courtney Hurt (2012), Amanda Thompson (2010), Ashley Walker (2009)

Examples from this year's senior/draft class: Aleighsa Welch, South Carolina; Nneka Enemkpali, Texas; Alexyz Vaioletama, USC

True shooting percentages under 55%: This applies more to centers than "power forwards" - a "stretch four" who takes shots further away from the basket would be expected to have a lower scoring efficiency (e.g. LSU's Theresa Plaissance & Nebraska's Jordan Hooper in 2014) - but even those posts who are more perimeter oriented are more successful when they do hit this threshold.

Notable past examples: Nikki Green (2013), Chanel Mokango (2010); Anna Prins (2013), Kayla Standish (2012); Joslyn Tinkle (2012), Cassie Harberts (2014), DeNesha Stallworth (2014), Michelle Plouffe (2014), Mikaela Ruef (2014)

Examples from this year's senior class: Isabelle Harrison, Tennessee; Sara Hammond, Louisville; Alexyz Vaioletama, USC

Low free throw rates: Post players with low free throw rates (FTA/FGA under 40%) tend to struggle. The reason(s) for the low free throw rate does matter, but the low rate itself suggests reason to take a closer look at how someone is playing.

Notable past examples: Lynetta Kizer (2012), Haley Peters, Duke (2014); DeNesha Stallworth, Kentucky (2014)

Examples from this year's senior class: Aleighsa Welch, South Carolina; Chelsea Gardner, Kansas; Cyesha Goree, Michigan; Sara Hammond, Louisville; Alexyz Vaioletama, USC