1 Skill Every Top Under-23 NBA Star Still Needs to Add

Any player who even flirts with the "star" label before turning 23 is already a winner. It's hard to make an impact in the NBA, let alone a major one, without struggling through that early-career learning curve.

That's a roundabout way of saying anyone who makes this list is an exceptional talent. All we're saying here is that each young star has room to improve.

Only players who'll be in their age-22-or-younger season in 2020-21 qualify, which means we have to cut Bam Adebayo, John Collins, De'Aaron Fox, Brandon Ingram and Jamal Murray (among others) from consideration. Not all of those players would qualify under the "star" requirement either.

Speaking of which, "star" is a fuzzy term. We won't require a particular award or honor, but All-Star berths and MVP consideration certainly help. These guys must already have highly productive track records to go along with significant buzz and notoriety. Those parameters will cost us Michael Porter Jr., Deandre Ayton and Shai Gilgeous-Alexander—all promising talents who fall a little short of stardom for now.

To the few under-23 talents who made it, congratulations! Now you get to have your games picked apart.

Tyler Herro, Miami Heat: Passing

Should we consider Tyler Herro a star? Has Jack Harlow named a song after another under-23 player? Herro has a case to escape honorable mention—and not just because of his pop-culture clout. He also blew up in the bubble, shining during meaningful games and editing several chapters of whatever book chronicles playoff rookie records.

The 20-year-old is on a star track, but he's not quite there yet. We can't put him on the level of the five players we'll feature momentarily. But, just for posterity, Herro has to improve his passing. He'll be a stellar scoring guard on or off the ball if he changes nothing, but better reads and quicker decisions could unlock a whole other level of his game.

Last season, Herro amassed at least as many turnovers as assists in 30 of his 55 regular-season games and ranked in the 10th percentile among combo guards in assist-to-usage ratio.

Jaren Jackson Jr., Memphis Grizzlies: Rebounding

Jaren Jackson Jr. isn't yet recognized as a star, but teammate Ja Morant's rise to prominence will draw more eyes to the Memphis Grizzlies and, eventually, the floor-stretching, rim-protecting big man will get his due.

You just can't find the kind of size and marksmanship Jackson Jr. provides. He and Karl-Anthony Towns are the only players 6'11" or taller to ever post a season with at least 6.0 three-point attempts per game and a conversion rate north of 39.0 percent. Both pulled off that trick last season.

Rebounding is Jackson Jr.'s bugaboo. He ranked in the ninth percentile among bigs in defensive rebounding percentage last season. If offensive rebounding were the sole issue, you could get away with blaming it on Jackson being routinely stationed beyond the arc, cutting down his chances on the glass. But there's no excuse for such poor work on the defensive boards. He has to get better there, even if the on-off splits show Memphis' defensive rebounding as a team is marginally better with Jackson on the floor.

Volume and shot versatility aren't issues with Luka Doncic's long ball. He got up 8.9 treys per game last season and had no trouble firing away with side steps and step-backs from all manner of tough angles.

The threat of him abruptly pulling back and gunning from 28 feet off the dribble was a real weapon for him, which is somewhat surprising, considering Doncic only made 31.1 percent of his long-range attempts. It was particularly unusual that a lower percentage of his catch-and-shoot treys (28.0 percent) fell than the ones he attempted off the bounce (31.6 percent).

Despite relatively poor accuracy from distance, Doncic still ranked in the 77th percentile at his position in points per shot attempt. His supremely good finishing at the rim, where he ranked in the 94th percentile in conversion rate, more than balanced out those errant threes.

It's hard to say exactly why Doncic hasn't been more reliable beyond the arc. He has incredible touch and feel, a high release, ridiculously good footwork that allows him to create space and the terrifying threat of his drives to deter defenders from hugging up too close. It's tempting to argue that Doncic's inaccuracy actually stems from his unique ability to get bad shots off. That feels a little too much like fawning, though, and that logic ignores Doncic's poor performance on standstill threes.

It's difficult to imagine what Doncic could do if he became a knockdown three-point shooter. The word "unfair" springs to mind, as do thoughts of, say, four or five MVP awards. If his growth from his first to second year is any indication, we won't have to imagine anything. Doncic will just show us.

Ja Morant turns it over a little more often than you'd like, and it's disappointing that his obscene athleticism and preternatural court sense have yet to produce a major defensive impact. But we can chalk those shortcomings up to youth and the natural learning curve that accompanies the amateur-to-pro transition.

Give Morant enough reps, and he'll sort that stuff out.

The key to getting those reps, though, is health. Morant can't smooth the rougher edges of his game if he's not on the court, and his style of play as a rookie was reckless enough to raise concerns about his long-term availability.

We just can't have falls like this, even if it costs us spectacular highlights like this.

If ensuring safety isn't persuasive enough, or if you're not sure discretion is a skill, we can re-frame things this way: Morant's scoring efficiency at the rim is surprisingly middling, ranking in the 50th percentile among point guards. Maybe if he didn't try to spike a poster dunk, or pull off a 360 layup or generally treat so many drives like opportunities to attempt death-defying acts of aerialism, that conversion rate would get a little better.

Morant has plenty of tools with which to approach his job. His floater is already feathery. His passing is elite, and he draws enough attention on drives to make a living with kick-out passes to open shooters. Everyone wants to see the Grizzlies point guard obliterate the rim, but Morant can get better by toggling off "attack mode" once in a while.

Jayson Tatum has a penchant for pushing off, but "quit committing offensive fouls" isn't really a skill a player develops.

Finishing craft is something Tatum can improve. Growth in that area would not only help him tweak a shot profile that could benefit from a higher percentage of attempts at the rim, but it would also result in more trips to the foul line—which are better than dejected trots to the other end of the floor after being whistled for an off-arm shove.

Tatum isn't bad as a foul-drawer. He ranked in the 62nd percentile among forwards in shooting fouls drawn in 2019-20. Initiating contact is half the battle, and Tatum already does that fairly well. His problem is absorption of contact; he doesn't tend to finish well when hit.

Among forwards, his and-one percentage (the frequency with which he drew a shooting foul and made the basket) ranked in the 23rd percentile. Maybe this is why Tatum tries to create space and prevent hard fouls by pushing off. Whatever the cause, the effect is a drain on efficiency.

Tatum's skill level is beyond question, and he may already have the most complete two-way game of any player on this list. It won't be difficult for him to add the tricks he'll need to shelve his push-offs forever. Varied footwork, deceleration and even a simple "jump stop, up fake" combo could easily be in his bag by 2020-21.

In Tatum's defense, those tricks usually belong to veterans or vertically-challenged guards (think Kyle Lowry on both counts) who need them to score near the basket. If Tatum can develop those dark arts and combine them with his size and touch, defenders won't have a chance.

Slight of frame and small in stature, Trae Young has a low defensive ceiling.

But he can be better than he's been over his first two years—if only because he probably can't get any worse.

Young shoulders a heavy offensive load for the Atlanta Hawks, which means that even if he had better tools, it wouldn't be fair to ask for consistent shutdown efforts on D. There isn't a point guard in the league who matches Young's high-usage offense and also defends at an elite level. The comparison has been inescapable since Young was in college, but Stephen Curry-level competence should be the goal.

An intelligent player with fantastic vision, Young has also already mastered the art of foul-baiting. He suckers opposing defenders into cheap hacks better than most 10-year veterans. So we know Young is an expert at anticipating his opponent's movements and reacting with exceptional quickness when they're off balance.

So why was he ninth among Hawks players (among those who played at least 500 minutes in 2019-20) in deflections per 36 minutes? And why was his steal rate in the 30th percentile among point guards?

Young's lack of length is a factor, but there are plenty of examples of smaller guards being either a) more disruptive, or b) useful as off-ball defenders who can scamper around screens and stay glued to shooters. Few, if any, of them have Young's smarts and court sense.

Steals and deflections are just a tiny part of defense, but if Young is never going to be a great on-ball stopper, he should at least be able to cause some trouble off the ball.

If Zion Williamson's alarmingly poor attentiveness and help instincts as a rookie owed to missed time, injury and the resulting poor conditioning, maybe the New Orleans Pelicans don't have a problem.

But if defensive awareness is one of those "you've got it or you don't" unteachable skills, it's going to take a ton of work to build the right roster around 2019's No. 1 pick.

Williamson was a useful off-ball defender at Duke, where he generally guarded 4s and played free safety. His speed and lift helped him produce 1.8 blocked shots per game, and he led the ACC in steals. But in the NBA, Williamson seemed to lack feel, and his positioning could hardly have been worse. The out-of-nowhere bursts into passing lanes were few and far between—especially in the bubble.

Too often, Williamson failed to react to (or even see in the first place) cuts from players he was supposed to be monitoring. As a pick-and-roll defender, he was equally lost, frequently winding up in no-man's land, obstructing neither the ball-handler nor the big rumbling down the lane.

He was slow to close out to shooters and constantly lost track of his own man. Williamson also ranked in the sixth percentile in defensive rebound rate, which suggested his low activity level extended past the point when an opponent's shot went up.

An offseason of film study and cardio should better position Williamson to succeed on D, and it's still far too early to declare him a lost cause on that end. There's just no way to argue he lacks the physical ability to positively affect the action—on and off the ball.

Williamson can improve. For the Pelicans' sake, he'd better.

Stats courtesy of NBA.com, Basketball Reference and Cleaning the Glass. Salary info via Basketball Insiders.