Chelsea have confirmed that Antonio Rudiger will miss the rest of the season after having successful surgery on his knee in Rome on Tuesday.
It appears the injury to Rudiger's left knee meniscus will keep him out for several months with Chelsea expecting the defender back "early next season".
The German centre-back limped off during the second half of the Blues' 1-1 draw at Manchester United on Sunday, and was operated on by Professor Pier Paolo Mariani in the Italian capital.
Mariani's previous clients include Francesco Totti and he most recently operated on Newcastle's Florian Lejeune's knee injury.
Rudiger's absence comes at a crucial point in the season for Chelsea as they chase success in Europe and a top-four place in the Premier League.
The 26-year-old will be sidelined for both legs of the Europa League semi-final against Eintracht Frankfurt, as well as the potential final.
He will also miss the final two league games of the season, against Watford and Leicester, with Chelsea looking to hold on to fourth spot and qualification for next season's Champions League.
Rudiger is likely to be replaced by Andreas Christensen, given that club captain Gary Cahill has been frozen out by Maurizio Sarri this season.
Rudiger, who has 30 caps for Germany, has made 44 appearances for Chelsea this season, scoring once.