The suggestion came in July 2016, shortly after Kevin Durant rocked the NBA by signing with the Warriors: “You should go after All-Defensive team.”

Golden State assistant coach Ron Adams, reunited with his former pupil six years after last working with him in Oklahoma City, had long seen in Durant all the tools — the 7-foot-5 wingspan, the 33½-inch vertical leap, the unyielding competitiveness — to become a dominant defensive player. However, a daunting offensive workload made it tough for Durant to give the consistent defensive effort an All-Defensive team selection requires.

Now, 17 months after Adams encouraged him to become one of the NBA’s premier defenders, Durant is exceeding even his own expectations. A player known primarily for being one of the best scorers in league history has emerged as the front-runner for Defensive Player of the Year.

“It’s cool that people are starting to recognize me for being more than just a scorer,” Durant said recently. “I’ve been trying to shake that rap since 2012. ... I try to impact the game as much as I can on both ends of the floor.”

Durant boasts the ideal defensive skill set for the modern NBA’s small-ball revolution. Thirty pounds heavier than he was as a rookie, Durant is strong enough to bang against centers in the post and agile enough to defend guards along the perimeter. His size and experience make him a vexing matchup for some of the league’s most skilled wings.

Nearly halfway through the season, Durant leads the NBA with 71 blocks. Opponents are shooting 51.9 percent inside of 6 feet against Durant, or 9.7 percent worse than their season averages, which is fourth only to New York’s Kristaps Porzingis, Philadelphia’s Joel Embiid and Miami’s Hassan Whiteside among players who contest five or more shots in that range per game.

Earlier this season, when reigning Defensive Player of the Year Draymond Green missed five of six games with a sore right shoulder, Durant anchored a defense that allowed a league-best 97.6 points per 100 possessions. In the Warriors’ Christmas Day win over Cleveland, he swatted five shots and held LeBron James to 7-for-18 shooting.

“I think he is (a Defensive Player of the Year candidate), if not the leading candidate,” Green said after watching Durant block three shots in Wednesday’s rout of Utah. “I don’t think it’s really a race right now. The way he’s been playing on the defensive side of the ball has been spectacular.”

It only helps Durant’s candidacy that the three finalists for the 2017 Defensive Player of the Year award — Green, San Antonio’s Kawhi Leonard and Utah’s Rudy Gobert — have yet to make a strong case. Hampered much of the season by that nagging shoulder injury, Green’s defensive intensity has fluctuated. Leonard missed the first 27 games of the season with a quad injury, and Gobert has been in and out of the lineup with a knee issue.

Outside of perhaps Oklahoma City’s Paul George, who easily leads the NBA with 2.5 steals per game, no one other than Durant has gained much traction as a Defensive Player of the Year candidate. However, that hardly means Durant is a lock for the award.

As the season progresses, voters will scour the numbers for a worthy crop of hopefuls. A review of the advanced analytics might not reflect favorably on Durant. His defensive real plus-minus — a stat measuring a player’s average impact on his team’s defense by points allowed per 100 offensive possessions — is 0.31, which ranks 34th among small forwards.

It also could hurt Durant that Defensive Player of the Year voters tend to prefer traditional centers. Before Leonard won his first of two DPOY awards in 2015, prototypical centers got the nod 21 out of 23 seasons. Embiid or Whiteside, both of whom would represent a continuation of the halcyon days of Dikembe Mutombo, Alonzo Mourning and Ben Wallace, might emerge as contenders as the season progresses.

Such possibilities don’t concern Adams, who knew Durant as a gangly, offensive-minded 19-year-old when they first started working together in Oklahoma City nearly a decade ago. What excited Adams, one of the NBA’s most-respected defensive gurus, was that Durant was interested in becoming a two-way force.

When Durant checked out of games, he often asked Adams to assess his defense.

“At that time, consistency was the issue,” Adams recalled. “To be great defensively, you have to bring consistency every night. It’s the hardest thing.

“This year, you’re seeing him bring that energy, that intensity every night.”

Connor Letourneau is a San Francisco Chronicle staff writer. Email: cletourneau

@sfchronicle.com. Twitter: @Con_Chron

Durant’s defense

A look at how the small forward’s defensive stats rank in the NBA and among his position:

Durant avg. NBA rank SF rank Rebounds 7.0 34th 2nd Blocks 2.22 3rd 1st Steals 0.78 117th T30th

Note: Rankings through Saturday