Kentucky's Julius Randle looks the part of a big-time prospect. At 6'9 and 250 pounds, he's a 19-year-old with the body of a grown man. His combination of size and athleticism makes him nearly indefensible at the college level. Kentucky has been up-and-down in non-conference play, but Randle has lived up to the hype. He is a double-double machine averaging 18 points and 11 rebounds on 57 percent shooting.
But when you project his game to the NBA, there is one glaring flaw that would make me nervous if I used a top-five pick on him.
Randle is built like a Tyrannosaurus Rex: all torso and no arms. He has a 6'11 wingspan, per Draft Express, which is enormous in most contexts, but not the super-sized world of the NBA paint. When matched up against the best power forwards in the world, he's going to have a significant length disadvantage, a problem that could impact his game on both sides of the ball.
In almost any basketball context, having longer arms than your opponent is helpful. The guy with the longer arms can shoot over the top of of his defender. On defense, he can play a step farther back and still contest the other guy's shot. He has an easier time reaching for rebounds and getting hands in passing lanes. The closer you get to the basket, where there is less room to maneuver, the more important this becomes.
I learned this from personal experience. I was a 6'4 post player in high school, backing up guys who were 6'8 and 6'6. They both played D1 basketball, but I could still give them trouble in practice because I had really long arms. I had the length to make up for my lack of height, which made me comfortable matching up with them in the post. The best interior defenders in the NBA all have out-sized wingspans.
In writing this article, I looked through the DraftExpress measurements database for the wingspans of every starting power forward in the NBA. It's not comprehensive, as I could only find data on 22 of the 30 starters, but the numbers are not encouraging.* Randle's 6'11 wingspan ranks dead last. The average is well over 7'0; even undersized 4s like Paul Millsap (7'1.5) and Brandon Bass (7'2.5) have an advantage.
Only three of the 22 I found have wingspans below 7'0: Blake Griffin (6'11.25), Kevin Love (6'11.25) and Thaddeus Young (6'11.5). That's quite the trio, but it's also a group that screams "survivorship bias." In other words: You have to be a really good player to survive as a short-armed power forward in the NBA.
Randle is really good, but not in the ways Griffin, Love and Young are. Randle can play above the rim, but he's not in Blake's category as an athlete. Pretty much no one is. And while Randle has some perimeter skills, he's hardly the ball-handling and passing wizard Blake has become. Love is an elite three-point shooter and passer, two skills Randle has not shown at Kentucky. Young is a small-ball power forward who plays 20-plus feet from the basket and started his career at small forward.
Randle is often compared to Zach Randolph, another 6'9 left-hander. Z-Bo, though, has some of the longest arms at the position in the NBA. His wingspan is not in the DX database, but a Google search of "Zach Randolph wingspan" turns up results in the 7'4-7'5 range. That explains how he consistently scores over bigger and more athletic defenders; he has arms like a condor. Griffin's 6'11.25 wingspan, in contrast, is one reason why he can struggle in post.
That doesn't mean Randle won't be able to score at the next level. Even without great length, he's got a massive frame, a high motor and a nose for the ball. However, he will have to diversify his offense to thrive. In college, he mostly bullies power forwards who can't match up with him physically. In the NBA, he will have to be a better shooter and he will need to use his right hand. No matter where he is on the floor, he always goes back to his left. It's funny when you start watching for it.
The real concerns are on the other end of the floor. Randle averages 0.1 steals and 0.7 blocks, awful for a big man with his athleticism. Kevin Pelton of ESPN Insider has found that block and steal rates in college are important tools when projecting big men prospects. I suspect that's because they capture the problems players with comparatively short arms can have.
Here's an example of Randle "protecting" the rim in Kentucky's win over Louisville:
Russ Smith is 6'0 and 165 pounds. The guards are a lot bigger in the NBA.
Individual defense might be an even bigger issue. It's not something I recognized immediately, because so few college big men have the length and skill to score over the top of Randle. For me, the eye-opening experience was Kentucky's loss to Baylor, when he was matched up with fellow Dallas-area big man Isaiah Austin (7'1 and 225 pounds with a 7'3 wingspan).
Austin talked a bunch of trash beforehand, like he knew Randle had no chance of guarding him, and that's exactly how it played out in the few first minutes. Austin took Randle to the block and hit a fadeaway, and then he went out to the perimeter and hit a pull-up three. At halftime, John Calipari switched defensive assignments, putting Willie Cauley-Stein on Austin and hiding Randle on Baylor's other big man. Few NCAA teams have two NBA-caliber big men, so Randle's individual defense is not a huge concern for Kentucky. That won't be the case at the next level, though.
It's hard to build around a player with Randle's skill-set. He is a post-scoring big man who can't protect the rim. If you play him with a big man who can't stretch the floor, there won't be much room in the paint for him to operate. If you play him with another big man who can't protect the rim, your defense will be limited. There aren't many NBA centers who can shoot, block shots and play hi-low to preserve proper spacing. Randolph didn't find much team success until he started playing with Marc Gasol, one of those rare birds. The same dynamic has blunted the impact Al Jefferson and DeMarcus Cousins make on their teams despite gaudy offensive numbers.
And while Randle should average a double-double in the NBA, his style of play is not conducive to the way the league is going. More teams are spreading the floor and playing with four shooting threats, which won't work with Randle, since he doesn't have the defensive chops to be the lone big man on the floor. He will have to be on a two-post team like Indiana or Memphis, one that slows the tempo, maintains spacing and throws the ball inside. However, that's a style many guards aren't comfortable managing.
In the right situation, playing next to one of those rare floor-spacing and rim-protecting big man like Serge Ibaka or Anthony Davis, Randle could be a really good player on a championship-caliber team. In the wrong one, though, drafting Randle could end up setting a team back significantly. In the NBA, the shorter your arms, the harder it is to reach your ceiling.
*: The missing eight: Kevin Garnett, Jason Thompson, Ryan Anderson, Glen Davis, Andrea Bargnani, Dirk Nowitzki, Zach Randolph, Amir Johnson.