There’s a potent reason 6-foot-6 Knicks point guard Tony Wroten was deemed a big risk by other teams after the 76ers cut him in late December.

According to a longtime mentor from Seattle, Wroten’s rehab from 2015 surgery on the ACL in his right knee was not his first one. Will Conroy, a University of Washington assistant who was on the roster of four NBA teams, told The Post Wroten tore the ACL of the same knee his junior year at Seattle’s Garfield High School while playing wide receiver for the football team.

Wroten blew out his knee reversing the field after a reception and missed his junior year of high school basketball.

“I had told him not to play football that year,’’ Conroy said.

When his right knee began hurting late in the 2014-15 season, the Sixers discovered damage to the grafts of that original surgery. The Sixers medical staff elected to do the entire ACL surgery again. According to Conroy, the belief was the high school surgery was rushed and done improperly.

The Knicks signed Wroten in March, knowing he wouldn’t play, knowing he would need more rehab, knowing he was still an injury risk. As late as April 8, Knicks coach Kurt Rambis called Wroten’s future “a complete unknown’’ and a source said then his legs still weren’t strong.

According to an NBA source, however, there is much greater optimism in the seven weeks since the season ended, with Wroten’s progression spiking. The source says Knicks president Phil Jackson, desperate for a backcourt penetrator, is considering Wroten to be the starting point guard next season.

“I wouldn’t count Tony out,’’ the source said.

Wroten, who played at Washington, went home to Seattle last week to work out with Conroy, who took him under his wing in grade school. The Knicks cleared Wroten for full contact two weeks ago.

“He’s got his explosiveness back,’’ Conroy told The Post. “He’s a top-20 talent. If he puts it all together, the Knicks have gotten a steal. He can really get into the lane and finish over the top. He just doesn’t have the same pull-up jumper as Russell Westbrook, but he’s got similar explosion.”

Though that could be hyperbole, Conroy’s remarks were reminiscent of an eyebrow-raising remark from Sixers coach Brett Brown in April.

“We were always trying to grow his perimeter game, but he had a downhill mentality that really at times was jaw-dropping,’’ Brown said. “With his size and athleticism, there was a wow factor. He was a little mini LeBron [James] playing downhill attacking the basket.”

The Knicks are likely to debut him in the Orlando summer league in July, though Wroten would be entering his fifth season.

“Usually players with multiple years in the league aren’t happy for summer league,’’ Conroy said. “He’s fired up. He hasn’t played in a while.’’

Wroten’s 2014-15 season in Philadelphia was cut short by knee surgery after 30 games. He returned for just eight games this past season, but his legs still weren’t right.

“He’s a big point guard, a tall kid that can do things,” Jackson said of Wroten. “Our process is going on, it’s a little underground, a little beneath the surface, but this is one of our desires, that we have to have a penetrator.’’