After he was nicknamed “Maple Jordan,” after he went No. 1 overall in the 2014 NBA Draft, after he won the 2014-15 Rookie of the Year award, Andrew Wiggins earned a far-less-enviable distinction: the league’s worst defender.

It was June 2017, and Wiggins, then 22, was beginning to receive as much attention for his ball-watching and lazy closeouts as his acrobatic dunks. To explain why it had tabbed Wiggins as the NBA’s “Least Defensive Player,” the website FiveThirtyEight.com detailed advanced analytics that suggested attempting a shot over Wiggins was the same as getting an open shot.

What made Wiggins so detrimental on that side of the ball, the site argued, was that he had defended the 10th most shots in the NBA in 2016-17 — by far the most by a below-average defender. This type of scathing critique came to define Wiggins. By the time the Warriors acquired him two weeks ago in a blockbuster trade with Minnesota, Wiggins had been widely dismissed as a high-usage scorer whose numbers didn’t serve winning.

Few in NBA circles are as discerning about defense as Golden State assistant coach Ron Adams, who believes that, if put in the right situation, Wiggins could blossom — not just into a capable defender, but into one of the league’s best. With a 7-foot wingspan, lateral quickness and a better basketball IQ than many might realize, Wiggins boasts the makings of a one-on-one stopper. What prevented him from realizing his defensive potential with the Timberwolves was inconsistent effort.

“I was a big believer in him before he came here,” said Adams, who has built a reputation over the past three decades as a defensive guru. “I love that kind of player, a player with length and athletic ability. He catches onto stuff quickly, smart guy. There’s a lot of positives there.”

The sample size is small, but Wiggins has shown enough in four games with the Warriors for even his critics to start thinking he could form a potent defensive partnership with Klay Thompson along the perimeter next season.

In his Golden State debut Feb. 8 against the Lakers, Wiggins made life difficult on LeBron James and Anthony Davis, repeatedly sneaking into passing lanes as he piled up five steals. Two nights later, Wiggins hardly looked overwhelmed as he matched up with the Heat’s Jimmy Butler for the bulk of the game.

In last week’s loss to the Suns, Wiggins blocked a career-high four shots, including three of All-Star guard Devin Booker’s attempts. On Thursday night, the Rockets’ James Harden and Russell Westbrook went a combined 1-for-5 on shots Wiggins contested.

Wiggins’ 1.8 blocks and two steals per game with the Warriors are triple and double his career averages, respectively. Among Golden State’s rotation players, only Draymond Green and Marquese Chriss have posted better defensive ratings than Wiggins.

“I feel like I’ve always cared about defense, but the coaches here have done a really good job of helping me understand the system and where to be in different situations,” Wiggins said. “Whenever I’ve had a question, Draymond’s been super helpful, just making sure I’m comfortable and encouraging me to do my thing.”

During his 5½ years with Minnesota, Wiggins showed flashes of being a high-level on-ball defender. But given that he had so much offensive responsibility, he tended to slog through defensive possessions, watching the ball instead of his man and barely jumping to contest shots.

When the Warriors traded for Wiggins at the deadline, he ranked 430th among 481 NBA players in defensive real plus-minus — a stat measuring a player’s average impact on his team’s defense by points allowed per 100 offensive possessions. His steals rate tied for the second worst among all small forwards. According to Synergy Sports tracking, Wiggins ranked in the eighth percentile among defenders in points-per-play allowed.

It didn’t help that his teammates were often out of position. The Timberwolves never ranked better than 24th among the NBA’s 30 teams in defensive rating during Wiggins’ tenure, even though Tom Thibodeau — a defensive-oriented head coach by reputation — patrolled the sideline for 2½ of those seasons.

However, the Warriors are careful not to over-rely on analytics when evaluating a player’s defensive acumen. Some in Golden State’s front office thought that the chatter surrounding Wiggins had turned so negative that fans and analysts had stopped judging him fairly.

Based on conversations with those who knew Wiggins, Warriors general manager Bob Myers became convinced that Wiggins needed a change of scenery to regain his self-belief on defense. Even if he didn’t emerge as a lock-down defender, Wiggins would at least be an upgrade from D’Angelo Russell, whose effort on that end in 33 games with Golden State often was nonexistent.

“The thought wasn’t that he was a bad defender,” Green said of Wiggins. “He just hasn’t really been in a winning situation, and that’s when the defense gets the notoriety. He hasn’t been in that situation.”

Since Wiggins arrived in San Francisco, Adams, Green and assistant coach Jarron Collins have schooled him on the nuances of help-side defense. Instead of harping on his past shortcomings, head coach Steve Kerr’s staff has kept the conversation positive, telling Wiggins that — if he continues to make strides — he’ll have a chance at an All-Defensive Team selection next season.

That’s quite a lofty goal for someone who was considered the NBA’s worst defender less than three years ago. But from time to time, Wiggins delivers the kind of sequence that shows off his potential.

Late in the second quarter of Thursday’s loss to the Rockets, Wiggins took a hard screen from the 6-foot-5, 245-pound P.J. Tucker at the top of the key, shook off Tucker and, just as Harden was launching a 3-pointer, darted toward the arc to get a hand in Harden’s face. As the shot clanged off the back of the rim, Harden raised his arms as if to ask, “What just happened?”

“He’s one of those guys who people have said, ‘He’s overrated’ for a couple of years,” Kerr said. “He’s become underrated, because you look at what he does, you look at his size, you look at the way he defends. The guy is a damn good NBA player. It seems like people have forgotten that.”

Connor Letourneau is a San Francisco Chronicle staff writer. Email: cletourneau@sfchronicle.com Twitter: @Con_Chron