LAS VEGAS — Mitchell Robinson is certainly acting the part of an NBA player now.

According to league sources, Robinson, the Knicks’ 20-year-old project center who dazzled the Las Vegas summer league, has made an agent change already.

Sources indicate Robinson, a Chalmette, La. product, has moved on from agent Raymond Brothers and has inked John Spencer, who also reps Lance Thomas. Spencer is a former Knicks scout under Ernie Grunfeld.

The move comes after signing his first contract last weekend — a four-year deal for $6.4 million with a team option after both the second season and third seasons.

The size of the contract with the two team options is not the reason for the switch. Robinson was selected in the second round at No. 36. According to sources, those closest to Robinson thought he had a better shot at becoming a late first-round pick — with more guaranteed money — if the pre-draft process was conducted smoother and smarter.

The day before the Draft Combine, Robinson’s reps decided to pull him out. Robinson, according to sources, believed that was a mistake.

“He had trained two months just for the combine and he was ready for it,’’ one source said.

The Lakers had considered taking him at No. 25 and were ready to snare him at No. 39 if he had dropped, according to sources. Robinson also interviewed with just a small amount of teams, including the Knicks, and it’s unclear if he worked out for any teams. But not being at the Draft Combine became a red flag for teams picking in the first round.

Based on his double-double summer-league performance, in which he posted similar numbers to No. 1 overall pick Deandre Ayton, the 7-footer looks like a keeper — if still raw. Robinson averaged 13 points, 10.2 rebounds, four blocks and shot 67 percent.

ESPN’s draft guru Fran Fraschilla said in Las Vegas that Robinson would have been a lottery pick if he had stayed at Western Kentucky. He dropped out last summer after taking one summer class.

Though GM Scott Perry admitted after the draft the possibility Robinson would play in the G-League for Westchester after not going 5-on-5 for 14 months, Robinson’s shotblocking and athleticism around the rim demonstrated he may be ready for the Knicks full-time. The club has two centers, Enes Kanter and Luke Kornet.

Robinson didn’t take any jumpers — his points coming on alley-oops and putbacks, and he darted to the perimeter on defense to block a slew of shots. Coach David Fizdale has work to do, though, as he got beat off the dribble and was foul-prone.

“He’s very talented at what he does,’’ Fizdale said. “I didn’t know what to expect. I watched those [high-school] All-Star games but those games you don’t know. I had no idea what I was going to see. Once we got to practice, it’s the timing that stands out and how he get lobs and his motor was great. I knew the 5-on-5 would catch up on his body after a year away but his rhythm and timing to be this good, that was really impressive.”