On a rainy night in late March, Jacob Evans watched from the bench as the Santa Cruz Warriors came from behind at home to beat the Agua Caliente Clippers at the 2,505-seat Kaiser Permanente Arena.

To the casual observer, Evans might have looked like just another G League player waiting his turn to show he belongs in the NBA. But Evans, on assignment from Golden State for much-needed playing time, was making $1.9 million as part of his rookie contract. Meanwhile, his Santa Cruz teammates who got the nod over Evans in crunch time were earning $35,000 for the G League’s five-month season.

Nine months removed from hearing Golden State general manager Bob Myers tout him as a potential immediate contributor in the NBA, Evans was struggling to outperform players who strived for the guaranteed deal he already landed. This was just more motivation in a rookie year loaded with it. After an offseason overhaul that severely depleted the Warriors’ wing depth, Evans is making good on Myers’ faith in him.

No longer worried about getting pulled after a questionable shot or bad turnover, Evans, 22, has showcased renewed confidence as he carves out a regular rotation spot. With Alec Burks sidelined by a sprained right ankle suffered early in training camp, Evans emerged as Glenn Robinson III’s primary backup at small forward.

Gone are the awkward shooting mechanics that derailed Evans’ rookie season. In Thursday night’s season-opening loss to the Clippers, Evans slid into Shaun Livingston’s old spot in the substitution pattern, posting 14 points and four rebounds in 22 minutes. Evans’ four 3-pointers matched his total from last season.

Though he labored at times defensively, Evans guarded Lou Williams — long one of the Warriors’ biggest nemeses — much of the night, a sign of head coach Steve Kerr’s trust in him. As Evans works to shed the “bust” label that trailed him last season, he is making some inside the organization view him as a long-term building block. The Warriors are widely expected to pick up his third-year option Thursday.

“You can see the experience of Jacob having a year under his belt,” Kerr said. “He just looks a lot more comfortable out there than he did a year ago.”

When Myers proclaimed at Evans’ introductory news conference in June 2018 that Evans could have a meaningful role as a rookie, he didn’t know that the Warriors’ first-round pick had a lingering hand injury from college that affected his shooting motion. With missed jumpers mounting, Evans tweaked his playing style in preseason, concentrating more on slashing to the rim than hanging along the perimeter.

Because NBA swingmen must be at least adequate shooters, Evans was quickly buried on the depth chart. His locker was even split in two to accommodate two-way-contract player Marcus Derrickson.

In need of minutes, Evans made 18 trips to Santa Cruz, where his averages in 21 games — 11.2 points on 43.7% shooting, 3.4 rebounds and 2.5 assists — were far from the dominance typical of NBA players on G League assignments. Evans peppered former Warriors swingman Andre Iguodala with questions, stayed late after practices to hoist extra shots and made a point to arrive early to every team meeting.

But sometimes at night, he thumbed through the Twitter mentions dubbing him a mistake as the No. 28 pick. When such criticism wore on him, Evans would call his older brother, Demarquis, who reminded him how lucky he was to share a locker room with so many All-Stars.

It also helped that Kerr went out of his way multiple times to publicly laud Evans’ strides behind the scenes. After logging 204 minutes in the regular season, he made several meaningful cameos in the playoffs, displaying the defense that had compelled the Warriors to draft him.

According to NBA.com, Golden State outscored opponents by a 10.1 net rating with Evans on the floor in the playoffs — good enough for second on the team behind Kevon Looney. Like Evans, Looney had been anchored to the bench as a rookie, only to blossom into a franchise building block once he overcame nagging hip issues.

The Warriors believe Evans, equipped with a reworked shooting form, can follow a similar blueprint. In the Las Vegas summer league in July, Evans started at point guard, averaging 16.3 points, 5.8 rebounds and 4.8 assists per game.

“If I’m open, I’m going to shoot it,” Evans said. “I’ve been working really hard on my game. When I’m open, just taking it and knocking it down.”

Evans is one of only five returners from last season’s Warriors team, but he is seven months younger than rookie Eric Paschall. Sometimes, after he sees Evans explain a nuance of Kerr’s system to one of the nine newcomers, Paschall reminds Evans, “Hey, I’m an old man compared to you.”

That’s just fine with Evans. Seven months after he sat the entire fourth quarter of Santa Cruz’s close win over Agua Caliente, he is making a case to play in crunch time of NBA games — that is, if Kerr wants a defense-oriented wing to complement Stephen Curry’s shooting.

“Jacob has got a different kind of confidence on the floor right now,” Curry said. “He’s understanding how he can impact the game on both ends of the floor.”

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