Serbia national team and English Premier League leader Nemanja Vidic, a center-back, dislocated his shoulder and will not play for at least four weeks.
The 25-year-old player suffered the injury in the 4-1 victory against Blackburn on Saturday, when in the middle of the first half defending a corner kick, he awkwardly landed on the ground and dislocated his left shoulder, immediately leaving the field.
The defender, who scored 3 goals in 24 Premier League matches this season, will miss the UEFA Champions League quarter-final match against Italian team Roma along with team captain Gary Neville.
"We believe he won't be able to play for about four weeks, so his absence is very painful for us," said Manchester United's head coach Sir Alex Ferguson.
In addition to G. Neville, who has injured ankle ligaments, and N. Vidic, another defender from France, Mikael Silvestre, has also suffered an injury and dislocated his shoulder in the UEFA Champions League round of 16 match against Lille, and will not play for the rest of the season.