Zlatan Ibrahimovic is expected to miss the rest of Manchester United's season, according to Sky sources.
Ibrahimovic injured his knee during the second leg of United's Europa League quarter-final against Anderlecht on Thursday night.
Jose Mourinho, who said after the game he was "not optimistic" about the extent of the damage, is now set to lose his top scorer for the Premier League run-in and the rest of United's European campaign.
And with a contract extension still unsigned, there is the possibility Ibrahimovic has played his last game for the club.
The Swede was brought in on a free transfer after leaving Paris Saint-Germain last summer and signed a one-year deal with the option of a further 12 months.
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His 28 goals include Wembley winners in the Community Shield and the League Cup final, and 17 goals from 28 league appearances.
Juan Mata, with just six goals, is United's next-highest league scorer.