Fears persist over extent of Cech's torn calf muscle

Chelsea are hoping that the tear to Petr Cech's calf, sustained in the hard-fought goalless draw against Schalke in the Champions League on Tuesday, can be managed without the goalkeeper having to undergo surgery.

If an operation is required it is feared that the 25-year-old could be out for up to a month. Cech is certainly set to miss Chelsea's home league encounter with Everton this weekend, while the club will also want him to absent himself from forthcoming international duty – with the Czech Republic having two routine qualifiers for Euro 2008 – as he recuperates.

Sunday's match has also tentatively been ear-marked for the return of John Terry, although his optimism – that he is recovering quickly from the knee problems which have ruled him out for the past few weeks – is not universally shared at Chelsea.

The nightmare for the club would be to lose both Terry and Cech at the same time, as they did so damagingly last season, although the injuries are far less serious than the ones sustained in the last campaign and should not derail them as they did then.

Nevertheless Cech cut a disconsolate, frustrated figure as he limped on crutches onto the flight back from Germany after damaging his right calf in a first-half challenge.

And the way in which the manager, Avram Grant, explained to the club director – and Roman Abramovich's fixer – Eugene Tenenbaum in the departures' lounge suggested that the injury was severe. The Israeli made violent tearing signals with his hands as he spoke to Tenenbaum.

Still, after a scan yesterday Chelsea were sounding more optimistic, describing Cech's injury as a "small tear". If it is worse than that – and Cech is out for a month – then he would miss league games against Derby County and West Ham United and the Champions League tie away to Rosenborg as well as the Everton game.

It's hardly the most taxing list of fixtures and the stand-in captain, Frank Lampard, brushed aside the concerns in endorsing the credentials of Cech's understudy, Carlo Cudicini, who came on in Germany and kept a clean sheet. He has only previously played in the League Cup this season and was beaten three times by Leicester City."

"Without a doubt, he is basically a first-team goalkeeper," Lampard said of the Italian. "It's only because of Petr Cech and the way he has played in the last few years that Carlo has been there [on the bench].

"He has always been the professional that he is and when he comes on he always performs. For me, he is one of the best in the league, forgetting the fact that he is our second keeper. It's very impressive."

Which is more than Chelsea were against Schalke. A draw was highly flattering as they laboured, rode their luck and were indebted to some wayward finishing by the home side who twice hit the woodwork and were desperately unlucky. The performance punctured, a little, the euphoria of seven straight victories for Chelsea who, nevertheless, still lead Group B and need one more win to guarantee qualification.

"You cannot be pretty all the time," Lampard said. "We have won seven on the spin and you cannot keep playing better and better.

"We didn't play particularly well, it was a very tough game. Resilience maybe, bit of luck, I suppose you do need that at times and you have to come away and dig in sometimes. It was a very difficult game."

Champions League Group B

Results: Chelsea 1 Rosenborg 1; Schalke 04 0 Valencia 1; Rosenborg 0 Schalke 04 2; Valencia 1 Chelsea 2; Chelsea 2 Schalke 04 0; Rosenborg 2 Valencia 0; Schalke 04 0 Chelsea 0; Valencia 0 Rosenborg 2.

Remaining fixtures: 28 November: Rosenborg v Chelsea; Valencia v Schalke 04. 11 December: Chelsea v Valencia; Schalke 04 v Rosenborg.