Vincenzo Montella will miss AS Roma's must-win Group B match at Valencia CF on Wednesday.
The 28-year-old Italian international twisted his left ankle in the second half of the 2-1 defeat by Udinese Calcio, a loss which saw Roma drop to tenth in the 18-team division. Montella played the full 90 minutes at the Friuli stadium but will not feature against the Spanish champions.
Montella has played in all nine of Roma's group matches to date, though he is yet to score. It is the Giallorossi's inability to find the net which has left them at the foot of their section with no points from three matches. With just five goals, Fabio Capello's side are the lowest scorers remaining in the competition.
The Roma coach is now faced with something of a selection headache. Marco Delvecchio is also injured and Massimo Marazzina is ineligible to play after appearing in the UEFA Cup for his former club, AC Chievo Verona. A saving grace for Capello could be the return of captain Franesco Totti after he sat out last week's 1-0 defeat by Valencia in Rome with a back injury.
Totti is expected to partner Antonio Cassano in attack, and the duo will need to be in prime form at the Mestalla stadium against one of Europe's most parsimonious back lines. If Roma fail to win in Spain and either AFC Ajax or Arsenal FC win their showdown in Amsterdam then the Italian side will be eliminated from the Champions League.