The legendary Nerazzurri defender was carried from the field at the Renzo Barbera in obvious distress after a collision with Rosanero defender Salvatore Aronica
The 39-year-old Argentine was stretchered off at the Renzo Barbara after pulling off following a collision with Rosanero defender Salvatore Aronica.
Inter have now confirmed Nerazzurri fans' worst fears that their legendary captain's season, and perhaps even his career, is over.
"Javier Zanetti underwent tests at Pavia's Policlinico San Matteo on Sunday evening, after being forced off the pitch in the 17th minute of Inter's game against Palermo," a statement on the club's official website read.
"The scans carried out revealed the captain has ruptured the Achilles tendon in his left foot."
Zanetti, who will turn 40 in August, had previously expressed a desire to continue playing for a further year before calling time on his illustrious career.