Chelsea plays against Rosenborg

Chelsea's first Champions League match of the season against Rosenborg on Tuesday is about more than picking up crucial points. It's a chance for the Blues to get their faltering season on track.

Chelsea's slow start to the Premier League season has left it in fifth place after six games ahead of its match against the Norwegian champions.

With key players injured or out of form, Chelsea - the 2005 and 2006 English champions - have looked far less formidable than in recent years despite the offseason acquisition of top players including Florent Malouda and Claudio Pizarro.

The continued investment of billionaire owner Roman Abramovich means coach Jose Mourinho is under pressure to improve upon his side's Champions League performances. Chelsea has never won Europe's top team title and lost in the semifinals to Liverpool in two of the past three years.

"We're so desperate to win it," Chelsea captain John Terry said. "We're born winners here and that's going to keep us going."

Chelsea will have to improve drastically upon its early season form if it's to be a contender.

The Blues lost 2-0 at Aston Villa and drew 0-0 against visiting Blackburn in its past two Premier League games, with Saturday's scoreless draw meaning they have hit just seven goals in six matches.

That's despite an attack boasting Didier Drogba, Malouda, Andriy Shevchenko and Shaun Wright-Phillips, who seems to have finally become a regular for England on the strength of his club performances this season.

However, Drogba sat out the match against Blackburn having aggravated a knee problem against Villa and may not recover in time to play on Tuesday.

"For a month I've trained with pain in my right knee," Drogba wrote in a column for French magazine Sport. "Sadly, I've not been able to get rid of this discomfort. I've played four Premier League matches in this state and it is unbearable.

"The European Cup is a competition that makes me dream. It irritates me not to be there.

Shevchenko was again disappointing when he replaced Drogba for his first match of the season, and his form has been so poor for Chelsea since joining from AC Milan a year ago that he has been linked with a return to Milan and another former club, Dynamo Kiev.

With Drogba likely to miss out, the Ukraine striker may get another chance to impress on Tuesday, but one man who won't is Michael Ballack.

The Germany captain was left off Chelsea's roster for the Champions League group stage, with the club citing an ankle injury. However, Germany coach Joachim Loew has expressed surprise at the decision and said he expects Ballack to be available next month.

That has added to speculation that Ballack could be sold, as early as January.

Whichever team Mourinho fields, Rosenborg is unlikely to pose a strong threat to Chelsea, which is unbeaten at home in the Premier League since March 2004. It has lost at home in the Champions League since then, but that was to eventual champion FC Barcelona in 2006.

The Trondheim team is in the Champions League for the 11th time and was a regular throughout the 1990s, but has one away win in 19 Champions League matches and lost 5-1 to Arsenal on its last visit to an English club.

Rosenborg lost 2-1 at IK Start at the weekend and is fifth in the Norwegian league, 10 points behind leader Brann Bergen after 19 matches.