Devin Booker’s next challenge: Evolving on defense like he has on offense

Devin Booker already put to bed that his destiny as an NBA player ends with him as a deadly spot-up shooter and nothing more.

In less than a full season, the Phoenix Suns’ rookie guard already finds himself in a third wave of offensive evolution. He began the year as a three-point specialist off the bench, then found himself forced into role as a top option.

In 16 games through the month of March, his scoring has spiked to 22.4 points per game thanks to extended minutes, and his success inside the arc and at the foul stripe (5.6 free throws per game) has blended well with a play-making ability that ESPN’s Zach Lowe covered in detail a few weeks back.

As times get tough and defenses adjust, a 19-year-old so consistent in his attitude and production is promising enough.

So about that next step …

How big are those defensive concerns?

Booker ranks third-to-last — and just ahead of teammate Archie Goodwin — in ESPN’s Defensive Real Plus-Minus statistic. Maybe it’s an arbitrary advanced stat, but there’s an obvious correlation when it comes to the eye test.

Take Wednesday night for example.

Booker was the primary defender on Bucks swingman Khris Middleton to begin what became a 105-94 Suns loss in Milwaukee. It was another reminder that, for all Booker’s promising offensive signs on offense, the defense has a long, long way to go.

It’s a positive sign than many of Booker’s flaws will be solved when he adds strength.

Despite not looking completely overwhelmed and not being light in the weight department, at times it seems the Booker’s biggest challenges lie in simply pushing himself under, over and through screens.

On Wednesday, Middleton got going by brushing Booker off a screen high on the right three-point line before hitting a floater. Then, Middleton simply blew by the rookie.

Even when Booker maybe, kind of got fairly caught on screens and required help, Middleton hit tough fade-aways on the move.

His multi-dimensional abilities helped him establish prime real estate in the post to get a score over the rookie. Then the Bucks’ forward simply shrugged off Booker’s best efforts to push him far out of the paint on a clear isolation possession.

All of those plays saw Booker put in effort to no avail.

In regards to his team defense, maybe there’s more room to grow. Phoenix general manager Ryan McDonough admitted to Lowe that Booker’s rotational awareness off the ball could improve.

Below, Booker runs flush into a screen, then teammate Tyson Chandler. He floats in the paint, guarding nobody, before Chandler shoves him back to where Phoenix needs him.

Booker recovers before damage is done, but the lack of communication — with him not being on the screener on time — dooms the rotation behind him as John Henson ends up with an easy layup.

The context to Booker’s Real Plus-Minus’ and judging his learning curve of a team defense gets complicated when considering the Suns’ individual and team defense has been bad across the board. The defensive philosophies went from above the team’s head under former assistant Mike Longabardi to overly-simplified after he was let go.

Still, much of this has to do with individual defense and Booker learning the NBA.

Based on the league’s SportVU data, which categorizes plays based on how close a defender is to a player taking a shot, Booker ranks 38th-worst in the NBA in defensive field goal percentage differential. He allows players he’s guarding to shoot 48.5 percent, or 4.7 percent higher than those players’ combined 43.8 percent average for the season.

Of course, a great deal of the bottom-50 players in the league in this category (with the only requirement being they played 20 games or more this year) are in the early years of their NBA careers or known defensive liabilities (Hi, Kevin Love), so take that for what it’s worth.

That Booker has now played 43 of 68 games as a starter and statistically fares better against better players than bench players such as, say, Goodwin — opponents shoot 5.6 percentage points better than their season average when guarded by Goodwin — shouldn’t be overlooked.

Neither should the simple fact that Booker is 19.

And to be clear about Wednesday night: Khris Middleton is a pretty darn good player. He just took advantage of facing the league’s youngest player, one whose teacher, Earl Watson, has heaped responsibility and challenges upon. Booker has only answered those with unwavering confidence and slow but steady growth on the offensive end.

When a healthier Suns roster returns next year and the whirlwind of a rookie year ends, will Booker evolve on defense just as he has on offense?

Follow @kzimmermanaz