Chris Mullin’s job just got a lot harder.

Two days before St. John’s opens the Mullin era against Wagner at Carnesecca Arena, prized freshman recruit Marcus LoVett Jr. has been ruled a partial qualifier by the NCAA, St. John’s announced Wednesday afternoon, creating a mammoth hole at point guard.

LoVett is allowed to practice, but cannot play in games this season as a result of the ruling. LoVett, who was supposed to fill the void left by Rysheed Jordan, is expected to remain a part of the program.

The school has exhausted the appeals process with the NCAA, but a source told The Post LoVett likely will hire an attorney and pursue a lawsuit against the NCAA.

In a statement critical of the NCAA Eligibility Center, St. John’s interim athletic director and legal counsel Joseph Oliva said the school “disagrees” with the decision, and feels some of LoVett’s rights may have been violated.

“We have advised Marcus and his family to consult with appropriate legal counsel about the options that may be available to challenge the NCAA ruling and the standards it applied in this process,” Oliva said.

“Marcus deserves to play and has done everything asked of him,” Mullin said in a statement.

The highly recruited LoVett, a top-50 prospect, attended three high schools, Providence High and San Gabriel Academy in California and Morgan Park High in Chicago. A source said the crux of the investigation centers on the fact LoVett was behind following his first three years of high school, but made up the credits by taking night and summer classes through Morgan Park. However, the NCAA questioned the amount of work he made up, and therefore felt he didn’t meet its requirements to be a full qualifier, the source said.

St. John’s was confident LoVett did enough to get through, with one source telling The Post “it should be an open-and-shut case.”

Without LoVett, Federico Mussini of Reggio Emilia, Italy, will have to run the point. Mussini struggled in two exhibition games, committing 11 turnovers and notching just four assists. Another highly regarded recruit, forward Kassoum Yakwe, is waiting to hear from the NCAA about his status.

Mullin was forced to recruit a virtually new team after taking over for Steve Lavin in April, bringing in nine players. LoVett, who averaged 25 points, eight rebounds and seven assists per game for Morgan Park last winter, was viewed as the centerpiece to this group, but now his status for this season looks iffy at best.