Carlos Baleba was forced off with a right hamstring injury during Manchester United's 2-0 Champions League defeat to Roma at Old Trafford on Tuesday.
The Cameroon international pulled up in the second half after a bright burst from midfield, grabbing his right hamstring as he powered into the box and went down in agony. He was replaced by fellow new recruit Youri Tielemans.
Roma race into early lead
United, looking to end a winless run of nine games, fell 2-0 down inside 18 minutes. Matias Soule capitalised on slack home defending to open the scoring inside Senne Lammen's near post before Donyell Malen doubled the advantage moments later when Ayden Heaven was adjudged to have used his hand to block a shot in the box.
Fans angrily aired their frustrations at the side's plight and vented their ire at the club's directors box, where chief executive officer Omar Berrada and director of football Jason Wilcox sat and watched the debacle unfold.
Fan protest and injury blow
Tennis balls were thrown onto the pitch and balloons flew down from the Stretford End in a planned protest from fan group the Stretford Enders.
Under-fire manager Michael Carrick's night got worse when Baleba, a summer signing who joined from Brighton late in the transfer window, was forced off. The midfielder arrived at Old Trafford with a pre-existing ankle problem that scuppered his start at his new club, making this another big blow.
