With the fall-out from international week fresh in their minds Chelsea will have to struggle against injuries and damaged reputations to win Saturday's potentially tricky tie at Middlesbrough.

The Cobham training ground treatment room is fast filling up, and with a number of players carrying bruised egos after poor showings for their countries, things are far from straightforward.

Among Luiz Felipe Scolari's biggest concerns will be midfield powerhouse Michael Ballack, who sustained a calf injury in his national team's qualifier against Russia on Saturday.

German national coach Oliver Bierhoff said: "Ballack missed training with a calf problem and is undergoing treatment. There is no way, at present, that he could sprint.

"We will be watching him carefully, but he knows better than anyone else how his body will react, and whether we can get him fit."

Meanwhile, goalkeeper Petr Cech is another big worry. It's not known whether he's fully recovered from a thigh muscle strain picked up playing for the Czech Republic against Poland last weekend.

Czech boss Petr Rada said: "Such injury news is unpleasant, but there is nothing we can do about it. Petr will now be treated by our doctors who will try to improve the current situation."