St. John’s won’t just be without its leading scorer and rebounder in Thursday’s Big East opener.

Following Julian Champagnie’s positive COVID-19 test last Friday, two more Johnnies — forward Joel Soriano and guard Tareq Coburn — tested positive Wednesday, sources told The Post.

And so, St. John’s will have only eight scholarship players available against Butler unless coach Mike Anderson chooses to burn the redshirt of freshman forward Drissa Traore. That would give the Johnnies a ninth player.

As of Wednesday night, the game was still on. The league stipulates teams have to play conference games if they have seven healthy scholarship players. Butler flew into Queens on Wednesday afternoon to face St. John’s, which was supposed to face Seton Hall on Monday.

That game was ruled a forfeit, since the Pirates didn’t have enough healthy players available. Three other league games were also forfeited, but the league voted on Wednesday to change its forfeiture rule due to the spread of the virus, according to sources, and will allow all games to be rescheduled. There will be no forfeits. That, of course, doesn’t mean every canceled game will be rescheduled. Arena availability and lacking mutual bye weeks could create issues, for instance, for the first Seton Hall-St. John’s game to be made up.

As for St. John’s, Champagnie is asymptomatic, Coburn has very mild symptoms, and Soriano is experiencing more pronounced symptoms. There is hope Champagnie can return for the Red Storm’s game against Marquette next Wednesday in Queens, but Coburn and Soriano almost certainly will be out for that contest and possibly the New Year’s Day game at Georgetown. Players who test positive have to Isolate for 10 days and pass a series of cardiac tests before rejoining the team.

St. John’s (8-3, 1-0) is coming off an ugly loss to under-.500 Pittsburgh at the Garden in which the absence of Champagnie was felt. It will have even more obstacles to overcome on Thursday now, although Butler also is far from full strength. It is not expected to have key players Bo Hodges (knee) and Bryce Nze (shoulder) due to injuries, and is coming off a 29-point loss to third-ranked Purdue. Like St. John’s, Butler struggled through most of its non-conference schedule and has a lower NET rating, 163 compared to the Johnnies 114.

Soriano, a 6-foot-10 Fordham transfer, is coming off his best game as a Johnnie, a 10-point, nine-rebound, four-block effort. Coburn, meanwhile, has struggled after starting strong, seeing his minutes dip significantly as he tried to juggle basketball and the school’s challenging physician assistant master’s program. There was hope that now that finals are over and the Hofstra transfer can focus solely on basketball for the next five weeks, he could emerge. But COVID-19 is standing in his way.

Their absences would likely increase the roles of freshmen Rafael Pinzon and O’Mar Stanley, who have been impressive despite limited minutes. Pinzon was a team-best, plus-eight in the loss to Pittsburgh and has provided much-needed shotmaking ability even with missing time due to a fracture in his left ring finger. The 6-8 Stanley has also played well in small doses and has shown a promising offensive skill set.

“I think you see these guys kind of growing before your eyes,” Anderson said. “They really are grasping what we ask them to do, and they are impacting our program, impacting our team.”

Anderson made those comments before he found out about the additional positive tests. Stanley and Pinzon will be needed even more now — if the game is in fact played on Thursday.