Manchester United have confirmed Mikael Silvestre dislocated his right shoulder against Lille on Wednesday.
The Red Devils progressed to the quarter-finals of the UEFA Champions League with a 2-0 aggregate win over Lille, but the victory came at a cost as Silvestre left the field on a stretcher.
The French defender landed awkwardly following an aerial challenge and manager Sir Alex Ferguson's initial fears of a dislocation have proved correct.
United have not put a timescale on the length of time Silvestre will be sidelined for, but he is likely to be sidelined for at least three weeks.
Ferguson has seen a number of key figures pick up injuries in the last week and it will be a blow to lose Silvestre as the season reaches boiling point.
Silvestre will definitely miss Saturday's FA Cup quarter-final with Middlesbrough and the Premiership clash with Bolton, but there is a two-week domestic break after United meet The Trotters on 17th March 17 due to international qualifiers.