The iconic midfielder sustained the injury in the match against Al Duhail, where Sepahan lost to the Qatari giant 3-2 in the 2025-26 AFC Champions League preliminary stage.
His absence will be a major setback for Sepahan ahead of the new season of the Iran Professional League (IPL).
Sepahan, headed by Moharram Navidkia, is scheduled to meet Malavan in Bandar Anzali on Tuesday.
Sepahan said it wishes Karimi a rapid and complete recovery, and looks forward to his return to the squad.