Guillermo “Willy” Hernangomez could make the jump from Europe to the NBA this offseason, and whenever the Spanish big man does, he will follow former teammate Kristaps Porzingis to the Garden and give the Knicks a steal Fran Fraschilla calls the ideal sign-and-stash pick.

Spanish outlet Encestando reports the Knicks are set to hand last year’s second-round pick a four-year, $4.5 million deal. Even though his agent, Andy Miller, told The Post, “There is no validity to the report,” that could be because the Knicks have to wait until July 7 to offer him a deal formally. Hernangomez’s rejection of two extensions from Real Madrid implies he could be Garden-bound.

“It’s great. He’s a terrific investment. Whether he comes over this year or next, you’re still talking about a young big guy [who can play],” Fraschilla told The Post. “The way I look at the ACB [League], if guys are playing in the ACC, in the Big Ten, that’s the equivalent of Double-A baseball. The ACB is Triple-A.

“He’s playing a lot higher level than your typical 22-year-old. He’s developing in a good league where the adjustment will be less pronounced than a college player’s. He’s playing at a much better level. The competition’s higher. These are professional players, grown men, in some cases former NBA players.”

Fraschilla, who coached St. John’s and Manhattan to the NCAA tourney, is among the foremost experts on international prospects. An ESPN analyst who covers the NBA draft, with a focus on foreign players, Fraschilla was among the first to start the Porzingis hype train.

He won’t put the same expectations on Hernangomez but said the 6-foot-11, 255-pounder — who doesn’t turn 22 until May 27 — was an ideal long-term buy.

“He’s a big-body kid. He was bigger and thicker — not bigger in terms of height but a wider, broader-shouldered player than Zinger. He was more of a power player, an around-the-basket guy, but he can play,” Fraschilla said. “Willy is just a good, young, solid big-man prospect, a four-man physical type of player. That’s what he was a year ago. … If you look in the dictionary under draft and stash, you’d see a picture of Willy. He’s an ideal guy to get your hands on and let him marinate in the ACB.”

That is exactly what the Knicks did. They used the fourth pick in the draft on Porzingis, then made a deal with the 76ers for the rights to Hernangomez, his Baloncesto Sevilla teammate. They watched the latter move back to Real Madrid from his loan to Sevilla, and average 6.7 points and 3.8 rebounds in league play, shooting a scalding 67.7 percent from the floor.

Now the Knicks and Porzingis are hoping for a reunion, with Porzingis expected to visit with Hernangomez during his offseason European trip. It would require the mid-level exception or cap space to ink Hernangomez for a deal over two years. But with big men Kevin Seraphin and Lou Amundson free agents July 1 and Derrick Williams having a player option, he’d quickly find a role.

“I hope he’s here. If it was in my hands, I’d obviously want him to be here. I think he really wants to be here. I’m not sure — both sides have to make a decision. I’d really love to see him here,” Porzingis told The Post in February. “He’s big, very good hook shot with both hands. He really knows how to hold his defender. He’s really good in the post. The triangle offense would fit very well.”

Hernangomez is regarded as strong, agile and a good rebounder if not the most disciplined defender or explosive leaper. And basketball is in his DNA.

His mother, Margarita Draeger, starred on the Spanish National Team in the 1992 Olympics, father Guillermo Hernangomez Heredero played pro in the ACB, 20-year-old brother Juan is a top NBA prospect at Movistar Estudiantes whom Fraschilla likened to Jonas Jerebko, and sister Andrea plays for the Estudiantes Junior team.

“It’s a basketball family,’’ Fraschilla said.

Knicks president Phil Jackson recently was seen eating in Greenwich with coaching candidate David Blatt, according to greenwichtime.com.

SNY reported the Nets and Knicks told players they are trying to buy a late first- or early second-round pick.

Nicolas Batum’s agents said they believe the Knicks would offer the Hornets star a max deal, but he would prefer to re-sign with Charlotte, according to Basketball Insider.