Duncan Watmore has suffered his second cruciate-ligament injury in less than a year and will miss the remainder of the season.
The Sunderland and England Under-21 forward only returned in September having spent nine months on the sidelines.
However, new Black Cats boss Chris Coleman has confirmed that the 22-year-old has again undergone knee surgery after injuring his knee during the 2-2 home draw with Millwall last weekend.
‘This season probably won’t happen for him,’ said Coleman.
‘I told Duncan on Sunday, if it’s bad news then the worst thing you can do is put a time on it, but he’ll be chasing time as he’ll want to be back.