Inter confirmed that captain Javier Zanetti ruptured the Achilles tendon in his left foot in Sunday's 1-0 Serie A loss at Palermo, thus putting his hopes of playing on for another season in jeopardy.
The 39-year-old Argentine was stretchered off at the Renzo Barbara following a collision with Rosanero defender Salvatore Aronica.
Inter has now confirmed its fans' worst fears that their legendary captain's season, and perhaps even his career, is over. The injury could keep Zanetti out for up to nine months.
"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.