SANTA CRUZ — Alen Smailagic was chatting with two friends outside the Santa Cruz Warriors’ locker room Friday night when a half-dozen fans gathered nearby.

“What’s his name again?” a middle-aged woman asked her husband.

“I’m not sure,” the man said, “but that kid’s going to be big-time.”

When his buddy alerted Smailagic to the small crowd forming behind him, Smailagic — at 18 years old, the youngest player in G League history — grinned as he began to sign autographs and pose for pictures. Five months removed from the rec-league-size gymnasiums of Serbia’s third division, he is emerging as a fan favorite and bona fide NBA draft prospect with Santa Cruz.

With a textbook 3-point shot, deft touch around the rim, confidence and a desire to improve, the 6-foot-10, 215-pounder is a developmental project who could make a front office look quite wise in a few years. Golden State recognizes as much, which is why some scouts around the league believe that it has tried to hide him this season.

Because Smailagic isn’t eligible for the NBA until June’s draft, the Santa Cruz Warriors — Golden State’s G League affiliate — have had almost half a year to evaluate him daily without fear of him getting called up by another NBA team. However, this puts the Warriors in a potentially tricky situation.

If Smailagic’s stock rises to the point where he is out of Golden State’s draft range (it’s slated for the No. 28 and No. 58 picks), it could be grooming him to help another franchise. That incentivizes the Warriors to develop Smailagic as much as possible while still limiting his exposure to other teams.

“If they really like him — and all indications are that they do — why would they put all this work into him, only to watch him become a building block elsewhere?” a Western Conference scout, speaking under the condition of anonymity, told The Chronicle. “It’s really next-level thinking on their part, to be honest.”

Two years ago, while on a scouting trip to Serbia, Santa Cruz general manager Kent Lacob watched Smailagic — then 16 — work out at a small gym in Belgrade. Smailagic expressed interest in pursuing a pro career stateside, but he was far from an NBA prospect.

In late October, when Santa Cruz traded up in the G League draft to acquire Smailagic (the No. 4 pick) from the South Bay Lakers, many G League executives were perplexed. Smailagic hadn’t played at any level higher than Serbia’s third division or the under-19 junior league. His only experience on a national team came at the 2016 U16 European Championship, in which he averaged 5 points and 5.7 rebounds in seven games.

The lone highlight video on YouTube from Smailagic’s time with KK Beko — a third-division team in Belgrade that has not produced an NBA player in its 33 years — shows a gangly teen draining 3-pointers in a cramped gym with a soccer goal sitting along the baseline.

Within a few days of getting drafted, Smailagic arrived in Santa Cruz alone and able to speak only a handful of English phrases.

Over the next several weeks, player-development coach Anthony Vereen walked Smailagic through the basics of being a pro in the U.S. Vereen got Smailagic, who is making $7,000 per month with Santa Cruz, situated in his room at the team hotel before showing him how to use a debit card and shop for groceries.

“The players are really good to me, and they are letting me play my game,” said Smailagic, whose English is now conversational. “They’re not giving me a hard time when I take a bad shot or something. They’re really nice to me.”

In his third G League game, despite having yet to grasp Santa Cruz’s movement-heavy offense, Smailagic came off the bench to score 16 points in a win over the Agua Caliente Clippers. Less than a month later, he posted 25 points and 12 rebounds in a loss to the South Bay Lakers.

ESPN’s Jonathan Givony — a leading NBA draft expert — then published an article that touted Smailagic as a “prospect on the rise.” In the piece, Givony wrote, “Smailagic will be studied closely next week at the G League Showcase in Las Vegas, as the dearth of international prospects — and particularly big men — in the 2019 class makes him an intriguing second-round prospect.”

A number of scouts and executives attended the G League Showcase with the sole purpose of watching Smailagic, only for Santa Cruz to sit him for both of its games in Las Vegas. Some saw it as an attempt by the Warriors to hide their most intriguing prospect, as first reported by Forbes.com. Santa Cruz contended that it wanted to maximize minutes for its call-up eligible players and that Smailagic needed a break after having played in only 25 games last year with his Serbian team.

“Looking back on it, the timing to rest him may not have been the best,” Lacob said. “To be honest, we didn’t anticipate the backlash that we got. We probably would’ve done it a little differently and not have sat him out of those games if we had known that. We didn’t intend to offend anyone.”

Regardless, NBA teams curious about Smailagic now have plenty of video on him.

The Hawks’ decision to call up center Deyonta Davis from Santa Cruz last week freed up minutes for Smailagic, who has averaged 14.3 points, 6.5 rebounds, 1.7 assists and 2.2 blocks over his past six games. In Friday’s home game against Agua Caliente, he flashed a mix of size and skill that has Golden State thinking he could be the ideal big man for the modern NBA, scoring 21 points on forays to the rim, 3-pointers and mid-range jumpers.

With the Warriors down by five midway through the fourth quarter, Smailagic asked his teammates during a timeout to give him the ball. “I’m better than that guy,” Smailagic said, referencing Agua Caliente forward Johnathan Motley, who played for Dallas last season and is on a two-way contract with the Clippers.

Smailagic scored Santa Cruz’s final four points, including a driving dunk with 32 seconds left, to lift the Warriors to a 113-109 win. As fans filed toward the exits, one turned toward his friend and remarked, “I think we just saw the next Nikola Jokic.”

“It’s been amazing just being able to help a kid who I believe is destined for some greatness,” said Santa Cruz head coach Aaron Miles, whose Warriors meet Oklahoma City in the playoffs Friday in Santa Cruz.

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