Sunderland forward Duncan Watmore is set to miss the rest of the season after scans revealed a cruciate ligament injury suffered in Saturday's win over Leicester.
Watmore has visited a specialist in London, and the 22-year-old is facing an extended period on the sidelines.
Sunderland said in a statement: "Sunderland boss David Moyes has confirmed that Duncan Watmore is likely to miss the rest of the Black Cats' season following the results of his scan on Monday.
"Results from the scans revealed Watmore has suffered cruciate knee ligament damage."
Watmore's absence will be a significant blow for manager Moyes who is already without Paddy McNair, Lynden Gooch and Lee Cattermole for the long term.
The former Altrincham youngster had started 11 games for Sunderland this season and proved a major factor in their recent revival.
But Watmore was stretchered off after a clash with Leicester's Christian Fuchs during the win over the Foxes, and the scans have realised Moyes' worst fears.
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Defeat to Arsenal on Saturday left Sunderland with two points from 10 Premier League games, equalling the lowest ever total at that stage.
Draws with Southampton and West Brom and eight defeats have seen David Moyes' side match the unwanted record set by Manchester City in 1995, a very different era for City.
Alexis Sanchez's second goal of the match, to seal Arsenal's 4-1 win, also left Sunderland's goal difference at minus-13 - one worse than City that season to edge them for the worst record.
That City team recovered to an extent, finishing on 38 points and being relegated on goal difference alone behind Southampton and Coventry.
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