The 30-year-old was forced off after just 14 minutes in Real Madrid’s 2-0 LaLiga win over Espanyol on the weekend.
Initial reports had suggested that he would be out for around five months after surgery, but it appears the injury is worse than first thought.
According to journalist Miguel Angel Diaz of COPE, this latest injury setback means Mendy is now likely to be out for over a year.
The update claims that his injury is far more serious than initially believed and that there is a tendon tear with bone separation.