Why did former Wisconsin guard John Blackwell remove his name from NBA Draft consideration and stick with his plan of transferring to Duke?
The decision could have been driven by getting feedback suggesting he would not be an early pick, and perhaps it was affected by whatever he can earn through Name, Image and Likeness (NIL) compensation and direct payments in this new era of college basketball. But there was one set of numbers that would — and in a year or so, probably will — make Blackwell an unusual NBA player.
Those numbers: Wingspan vs. height.
Everyone knows basketball players tend to be taller. The average NBA player is 6-foot-7. The average American male is 5-foot-9. (Fun fact: The average man in the Netherlands is over 6 feet, yet Stathead’s NBA database only lists 10 players born in that country, most notably the “Dunking Dutchman” — 7-foot-4 Rik Smits. Four of the other nine players were also 7-footers, while two more stood 6-foot-11.)
Stathead’s database finds that only 29 players who stood 5-foot-9 or shorter have played in the NBA. From the 2004-05 season onwards, only eight players of average or shorter height have debuted in the league.
Another average: For the average human, the ratio of wingspan to height is roughly 1:1. Having long arms would clearly be an advantage in basketball, helping players rack up rebounds, blocks and steals. But surely having long arms would just be a by-product of being tall, right? A 6-foot-9 player with a 6-foot-9 wingspan would be a more likely NBA prospect than a 6-foot-5 player with a 6-foot-9 wingspan, right?
So if we had to guess what percentage of NBA players have wingspan measurements that are less than their heights, what would we say? Maybe 40%? Or 25%?
Not even close.
The 2013 book “The Sports Gene,” which explored physiological reasons why some people have advantages in becoming athletes, found that at the time author David Epstein checked the numbers, only two players in the entire NBA had a wingspan measuring less than their height. One was Yao Ming, whose 7-foot-6 stature rendered any talk of his wingspan irrelevant. The other was sharpshooter JJ Redick.
And over the same span of time from 2004-05, when only eight players who didn’t exceed the USA’s average height debuted in the NBA, only 16 players who have been measured at the NBA combine and played at least one game in the NBA have had a wingspan measuring less than their height.
Blackwell would be the 17th.
(One caveat: Some players don’t participate in the NBA combine or don’t get measurements taken. The Stathead database lists 2,122 players who have debuted from the 2001-02 season onward, but one compilation of combine data only has 1,835 players, and that includes many players who didn’t make it into the league.)
Net wingspan doesn’t have as much variability as height. The average from combine data is about 4¾ inches. Nearly two-thirds of players are within two inches of that number.
But if Blackwell were to go on to have a successful career, he wouldn’t be alone. After a slow start to his NBA career, Redick had seven seasons in which he averaged more than 15 points per game. Current San Antonio Spurs teammates Mason Plumlee and Kelly Olynyk are each 13 years into productive careers.
If you’re seeing the names Redick and Plumlee and wondering if Duke has cornered the market on players in the category, you’re not wrong. Add Kyle Filipowski, and Duke alumni account for three players in this group. If Blackwell goes to the NBA after his Duke days are done, which seems likely, he’ll make it four. Former Duke player and current Duke coach Jon Scheyer never played in the NBA but was measured at the combine, and he also was in the net negative club.
The other aspect that may jump out here is that Plumlee, Olynyk and Filipowski are still playing. So is Tyler Herro, the Miami guard who has averaged more than 20 points per game each of the last five seasons and made the All-Star Game in 2025. Deni Avdija also has made an All-Star roster, Desmond Bane is a 20 point-per-game scorer, and Josh Giddey puts up solid numbers across the board.
Just 13 years after David Epstein found only two players with negative net wingspans, the NBA now has more than 10. Nikola Topić and Koby Brea are just breaking into the league, but Ty Jerome’s scoring average soared to 19.5 points in an injury shortened 2025-26 season, and Svi Mykhailiuk has a championship ring with the 2024 Celtics.
So maybe we’re seeing a Golden Age of Net Negative players?