Chelsea defender Antonio Rudiger will miss the rest of the season.
The Germany international was forced off during Sunday's 1-1 draw with Manchester United at Old Trafford.
Rudiger is now due to have an operation in Italy and won't play any part in Chelsea's final two Premier League matches or the conclusion of their Europa League campaign.
Andreas Christensen is likely to be brought in in place of Rudiger, meaning a return to the first-team squad for skipper Gary Cahill.
Chelsea sit two points ahead of Arsenal with two league games to play, with the London rivals going head-to-head for the final Champions League qualification berth.
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The Blues will face Eintracht Frankfurt in Thursday's Europa League semi-final first leg before hosting Watford on Sunday in their final home league game of the campaign.
Maurizio Sarri's men will take on Eintracht in the return leg at Stamford Bridge on Thursday week, before closing their Premier League campaign with a trip to Leicester .
Willian is another injury doubt for the clash with Frankfurt, although Maurizio Sarri has suggested he may recover in time.
Callum Hudson-Odoi will miss the rest of the season with an Achilles problem.
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Chelsea's draw with United put them in pole position to finish fourth ahead of their remaining games.
But Sarri admits they may still need to win both games to be sure of Champions League qualification.
“The draw is not so much important for us, because with the 1-1 here we have to win the last two matches otherwise we are at risk with the goal difference," he said.
