His trainer Marcell Scott can now laugh at the notion of Knicks 7-foot center Mitchell Robinson getting seasoning in the G-League as a rookie.

“I knew once they saw Mitchell on the court and saw all the stuff he brings to the table, the G-League would be eliminated from the conversation,’’ Scott told The Post in a phone interview. “I honestly think at the halfway mark, at the All-Star break, Mitch will be starting.’’

Scott, the mastermind behind Robinson’s long preparation for the NBA draft, was surprised by everything — and nothing — regarding Robinson’s stunning Las Vegas act three weeks ago at the nationally televised summer league.

Scott, who has trained Robinson on and off for four years, saw the athleticism and leaping ability on the Louisiana grass fields where he set up hurdles for the Knicks’ second-round sensation amid their intense training for June’s draft.

Scott saw the poise when he started to get off clean shots in a New Orleans gym against Pelicans superstar Anthony Davis, who volunteered his time two months before the draft to work out against the Louisiana high-schooler.

But Scott didn’t see him do anything in a game — for a long time.

“The last game was the [2017] McDonald’s All-American Game and I don’t call that a game,’’ Scott told The Post in a phone interview. “It’s a whole bunch of running up and down. So last time I saw him in a game was high school when everyone was 6-4 and under. I knew he was ready because he worked on a lot of stuff with Davis guarding him, but I wasn’t sure. I thought he wouldn’t get adjusted until the third game with the pace.”

Robinson was a revelation right from his debut. In the Knicks’ five summer-league games, Robinson, selected with the 36th pick in the draft, posted startling numbers. He averaged a double-double (13 points, 10.2 rebounds, four blocks)

“I was totally surprised he got adjusted,’’ Scott said. “The only thing we did was get up and down the track with sprints to have some endurance. But in a game, when you have someone physically pushing you the whole time? He said he was tired the first game but he did a good job catching up to the pace.’’

When Robinson wasn’t racing out on the perimeter blocking shots, the 20-year-old was throwing down alley-oop passes after not having played so much as a scrimmage in 14 months after dropping out of Western Kentucky to focus on NBA training. He shot 67 percent in Vegas.

After the summer-league finale July 13, a Friday, Robinson was back in the Louisiana gym with Scott the following Monday. So was Mike Miller, the Knicks’ summer-league and G-League coach. Miller headed there to watch Robinson’s workout for six days, making sure he was in a good hands with Scott.

Mostly, Miller wanted to see shot-making from the perimeter. Robinson’s Vegas points came off alley-oop slams and putbacks. In fact, he didn’t take a jumper.

“I said ‘what do you want us to do’ and he said ‘you’re covering everything we do’,’’ Scott said. “A lot of perimeter shots, jab steps. He was shooting 3s. He said he didn’t know he had that. In Vegas, you saw him on double picks and slashing to the hoop but he has a lot more to offer. You’re going to be shocked. He’s not a dunker all the time.’’

Since summer league, Scott also has worked on core exercises to get Robinson more balanced. Scott felt Robinson too often got pinned under the basket by Utah center Tony Bradley, causing him to foul repeatedly.

Scott hopes to get Robinson back together with Davis in August. Scott has worked with Davis for four years. Two months before the draft, Davis agreed to work with Robinson, who starred at Chalmette High, twice a week.

“He understood Mitch didn’t go to college, he heard the whole story,’’ Scott said. “He thought it was a good idea to help him out.”

Davis, though, was skeptical in the early going.

“I wanted Anthony to play D on him — it was all about trying to show Mitch you got a guy defending you just as long, tall and jumps just as high as you,’’ Scott said. “It was good for Anthony to play defense and push Mitch around. Every time he shot the ball, he put a hand in his face. It was terrible the first couple of sessions. Instead of shooting at his release point, he was double-clutching, trying to get his shot off by doing too much.”

Then Robinson adjusted and got off his shots more cleanly.

“I’ll tell you one thing — [Davis] didn’t think he was an NBA prospect at first,’’ Scott added. “Until he got on the court and saw he moves really good, was quick off the ground, [then] he understood Mitch was special.’’

Quickness to defend the perimeter is all the rage for NBA big men. Knicks coach David Fizdale raved that Robinson blocked more perimeter shots than the whole summer league combined. The lasting image of Vegas was Robinson shaking his head after rejected another one.

Scott says Robinson’s foot size is a key.

“He really gets excited off a blocked shot,’’ Scott said. “He covers so much space. He wears a size-13 shoe. Him being that tall, he’s got feet like a guard. He gets to the perimeter quick from the box, so he’s going to block or contest every shot. [His shoe size] is actually a blessing for him.”

And so it was no shocker Robinson set the summer-league record for blocks per game. And it goes back to the hurdles on the Louisiana grass this winter as others in his draft class played college games and attended class.

“It’s all about timing — that’s a God-given for Mitchell,’’ Scott said. “He gets off the ground so quick. … But one thing we worked at is those hurdle jumps. A lot of hurdles.”

Six hurdles were lined up in a row with Robinson required to negotiate the course six times.

“Hop over, hop over, hop over,’’ Scott said. “That develops the quads and keeps him explosive, the fast-twitch muscles.’’

NBA scouts didn’t get to see any of it at May’s draft combine in Chicago where Robinson’s former agent, Raymond Brothers, pulled him out the day before the sessions began. The Post reported after the summer league Robinson changed agents to John Spencer partly because of Brothers’ decision. One theory was the Lakers already had given Brothers a guarantee his client would be selected with the draft’s 25th pick, but that proved false.

“[Mitchell] was really mad, really pissed off,’’ Scott said of the decision to bag the combine. “He was ready to go. When the Lakers passed, all I thought was whoever gets him, they got a steal because he’s a lottery-type talent.’’

According to Scott, Robinson gave workouts to the Lakers, Bucks and Spurs, but backed out of his drills with the Knicks because of a sprained ankle. Instead, Robinson interviewed with Knicks general manager Scott Perry and president Steve Mills. It was enough despite Robinson’s innate shyness.

“I’ve noticed a difference since summer league — he’s more confident now,’’ Scott said. “More eye contact when he talks, articulating a lot better. He’s really understanding what it means to be a pro now.’’