Inter Milan's Colombian defender Nelson Rivas faces surgery this week on the right knee injury that he picked up in the Italian Serie A match against Bologna last weekend.

The club gave no indication as to how long the 25-year-old would be sidelined.

Rivas is the club's fourth defender to suffer injury after Italian World Cup winner Marco Materazzi, Cristian Chivu and the Brazilian Maxwell.

(Xinhua News Agency October 7, 2008)