Chelsea winger Arjen Robben could miss the rest of the season after opting to have surgery on a knee injury.
Robben has scored three goals for Chelsea this season
Robben, 23, returned from international duty with Holland on Thursday and after examinations, a decision was taken on Friday to operate on the knee.
Blues boss Jose Mourinho told Chelsea TV: "For me it's difficult to accept as he played two matches for his country.
"The next day he came here and he is injured. He needs surgery. We lose an important player maybe for the season."
Robben played the full 90 minutes in Holland's 1-0 Euro 2008 qualifying win in Slovenia on Wednesday.
The winger has scored three goals for Chelsea so far this season.
Mourinho said that Joe Cole was returning to full fitness and said the England international's return would ease his selection headache.
But he said he was still frustrated by the injuries at Chelsea this season.
As well as Robben and Cole, Chelsea have also lost captain John Terry and goalkeeper Petr Cech to injury.
"Joe Cole is coming back and maybe next week we have him," said Mourinho.
"But again we can never have our best team with every player available. But if I can lose one and gain one, it is not so bad.
"At this time we just want to have no more injuries because the matches are arriving and all of them are like finals.
"We want to be under pressure and being under pressure is to play every three days.
"We have fought a lot to be in this situation. It is difficult but we cannot complain, we need to be happy."