Louis van Gaal has confirmed Wayne Rooney suffered a knee injury during Manchester United's 3-0 defeat to Everton.
Goals from James McCarthy, John Stones and Kevin Mirallas sealed a famous victory for Roberto Martinez's side on Sunday 26 April as United lost their second consecutive league game.
And their afternoon took a turn for their worse when club captain Rooney limped off with two minutes remaining to be replaced by Robin van Persie.
Speaking to MUTV after the defeat, van Gaal confirmed the 29-year-old had suffered a knee injury, but insisted the club are still to determine its severity.
"Yes, Rooney was injured, van Gaal said post-match. "He had a shot on his knee, so we have to wait and see how heavy (serious) it is."
Marouane Fellaini was also substituted during the game, replaced at half time by Radamel Falcao.
The Belgium international was shown a yellow card less than a minute after being warned by referee Andre Marriner for a similarly rash challenge.
And van Gaal admitted the risk of the midfielder being sent off played a role in his decision to replace him against his former club.
When asked why Fellaini was taken off, he said: "Several reasons. He was booked and Everton players were provoking him. I wasn't sure if he'd last the full 90 mins."
Van Gaal slammed the performance of his side and admitted the defeat offered 'light' to Liverpool in their bid to close the gap on United and beat them to Champions League qualification.
United, currently fourth in the league, have a seven point lead over arch-rivals Liverpool but that gap could be reduced to single point by the time United next play.
Liverpool have a game in hand away to Hull City on Tuesday before they host Queens Park Rangers on Saturday. United welcome West Bromwich Albion to Old Trafford in Saturday's evening kick off.