Jack will have surgery later this week.
"Kadeem has worked extremely hard in preparation for the season," Rice said in a statement. "He will remain very much involved in all team activities and we look forward to his complete recovery."
The injury comes as a major blow to the already depleted frontcourt from last season.
Rutgers returns Gilvydas Biruta as its top post player along with junior Austin Johnson. Jack's missed minutes likely come to freshmen Derrick Randall and Greg Lewis, who each enrolled over the summer and have experience in the Jersey Shore Basketball League with the rest of the team.
Jack enrolled at Rutgers for the spring semester and red-shirted to save his four years of eligibility while still learning the ins and outs of the program.
At the earliest, Jack will be back in some capacity for the opening stretch of Big East play in 2012.