Sunderland manager Steve Bruce will have to cope with the loss of first choice goalkeeper Craig Gordon as his team battles to retain their Premier League status.
The Scottish international had been experiencing knee problems and after visiting world-renowned tendon specialist, Professor Hakan Alfredson, Gordon went under the knife in Sweden yesterday.
“Craig had the operation yesterday and it went well,” Bruce told the clubs official website.
“He'll be out for about four to six months now.
“Craig's been following a programme but when the specialist had a look at the knee again, we were left with no choice but to go ahead with the surgery.
Sunderland currently find themselves on a terrible run of form after taking only one point out of a possible 27.
Simon Mignolet looks set to keep the goalkeeping gloves for the remainder of this season and the start of next.
The 22-year-old Belgian has made 21 senior appearances in an impressive debut season in English football.