With Kristaps Porzingis developing Achilles soreness last week, one NBA scout with European connections believes Knicks coach Jeff Hornacek is overextending the 21-year-old Latvian, saying, “It’s worrisome.’’

Unsure how the injury occurred, the 7-foot-3 Porzingis missed his first game of the season Saturday in Houston because of pain in his right Achilles.

Porzingis, who started feeling pain on Christmas Day when he suited up with a bruised knee, is averaging 34.8 minutes per game (1,112 total) in his second season. As a rookie, the playing time for the lean Latvian hovered at 28 minutes.

“He’s just turned 21,’’ said the NBA scout, who has worked for multiple teams. “They’re draining Kristaps, putting more minutes on him than anyone. Physically he grew in the offseason. It’s a tremendous amount of strain on new material — ligaments, tendons, knee joints for a big guy. It’s unbelievable stress on his body.’’

Hornacek said after Saturday’s loss he planned to expand the rotation in 2017 and scale down minutes of some starters so he can get maximum effort at all times.

Porzingis’ shot-making took a dip in December, hitting just 40.1 percent for the month. He’s still averaging 20.1 points and 7.8 rebounds and could land in his first All-Star Game — if he stays healthy.

But the scout alleges Hornacek, on a three-year contract, views Porzingis in a shortsighted way instead of long-term.

“At this stage, they’re asking for it,’’ the scout said. “They’re shooting themselves in the foot. The problem is Jeff has to win and has to go with everything he’s got to win.’’

The scout said he agreed with a recent comment by Carmelo Anthony that lofty expectations are being placed on Porzingis too fast, likely due to his unique skill set for his size. Through the years, the scout hasn’t seen enough examples of “franchise players’’ out of Europe.

“There’s not too many cases when an international player becomes your franchise guy,’’ the scout said. “The best example is Pau Gasol. Dallas is the only one who came closest with Dirk Nowitzki. Marc Gasol is a rare exception, but Pau was a complement to Kobe Bryant. International players are more athletically and mentally geared to be more complementary to the American-produced star.

“Porzingis is a tremendous talent, with a lot of potential, but it’s still potential.

“The expectations are exaggerated and the physical demands on someone who is still growing is too. He’s very young, an excellent team player and has learned the mentality of a team game. With that mentality, it’s too early to assume he’s going to be the franchise.’’

Knicks president Phil Jackson has declined to talk to the media covering the club since Sept. 22, so publicly stated team objectives have grown cloudy.

“There isn’t a lot of clarity,’’ the scout said. “I was thinking NYK stands for Not Yet Knowing.’’