Roma defender Nicolas Burdisso could be ruled out of action for around six months after injuring his knee during Argentina's 2-1 World Cup qualifying victory over Colombia.
Burdisso, 30, was stretchered off on Tuesday following a 34th-minute collision with Porto midfielder James Rodriguez and initial assessments suggest he has badly damaged ligaments in his right knee and could face half a year on the sidelines.
The centre-back has been an important player for Roma this season and the absence of the former Inter Milan man will certainly be felt at the Stadio Olimpico.
Further tests are expected on Burdisso's knee in the next couple of days, which should yield a more accurate prognosis on how long he will be out for.
Giallorossi coach Luis Enrique's other centre-back options include Gabriel Heinze, Juan and Simon Kjaer.