Andre Villas-Boas has identified Chelsea's long-serving goalkeeper Petr Cech as one of a number of players who would be allowed to leave Stamford Bridge at the end of this season as part of the comprehensive overhaul of the club's ageing squad the Portuguese has planned should he remain in place as manager next summer.

The sequence of five defeats in nine games that has shrouded the 34-year-old's own future in uncertainty has convinced Villas-Boas that, should Roman Abramovich's patience continue to endure, Chelsea's playing resources will require substantial surgery. The former Porto manager decided last summer to give the current crop a chance to prove their worth but they are not likely to be afforded a second chance.

Some departures have been expected: neither Nicolas Anelka nor Didier Drogba have agreed new contracts, with the former likely to be permitted to leave in January, while the agent of the latter has suggested the Ivorian will "go wherever he is offered the most money" after turning down the chance to extend his stay in west London by one more year.

Similarly, the prospect of Villas-Boas clearing the decks of expensively remunerated fringe players – Alex, Salomon Kalou, Paulo Ferreira and Florent Malouda are all understood to be vulnerable, while it is hardly inconceivable Branislav Ivanovic or Jose Bosingwa might be sold – is not surprising, given the club's need to cut costs to comply with Uefa's looming financial fair play guidelines.

That Villas-Boas is prepared to part with Cech, though, is evidence of how deeply the Chelsea manager feels the club's malaise runs and how drastic he believes the solution must be. The Czech international,signed by Claudio Ranieri in February 2004 for £7m, has long been a cornerstone of the club's success, breaking a number of records as he helped Jose Mourinho's team claim successive Premier League titles. Though his form has been slightly more erratic since a sickening collision with Stephen Hunt, then of Reading, in October 2006, which left Cech requiring the headguard he has worn since, the 29-year-old is still widely regarded as one of the finest goalkeepers in Europe.

Villas-Boas feels his distribution is lacking when compared to Pepe Reina, of Liverpool, and Barcelona's Victor Valdes, both highly modern "sweeper-keepers," whose comfort with the ball at their feet enables the employment of a high defensive line. Villas-Boas admitted yesterday that "Petr, Ross Turnbull and Hilario have all been more involved in communication with the defensive line in the way they come out of goal to control the space," but it is not a role Cech excels in.

The Chelsea manager feels that shortcoming partly explains his side's defensive failings this season and he intends to make Thibaut Courtois, the 19-year-old Belgium international signed from Genk last summer, currently on loan at Atletico Madrid, as his first-choice next season.

However, Villas-Boas is at pains to point out that Chelsea's apparent frailty is not as serious as widely believed. As he stresses, his team have conceded only five more goals than Manchester City. "What people are comparing is the statistics to the first year Chelsea won the title [2004-05], when they had the most magnificent defence ever in Premier League history," he said. "It was never the same. Not one team has finished with numbers close to that Mourinho team."

Hit-List: The likely Chelsea departures

Petr Cech

Cech never recovered the same consistency, pre that Stephen Hunt tackle, which saw him amass a record 24 clean sheets in one season. Villas-Boas wants a 'modern' keeper to sweep up behind the defence and distribute effectively, in order to play his preferred high defensive line and possession game.

Paolo Ferreira

The Portuguese right back came with a hefty price tag but never truly adapted to the pace of the Premier League, it is miraculous he is even still at Stamford Bridge.

Branislav Ivanovic

Considered too small to be a centre back and not a natural right back, Ivanovic is a good squad player but could available if an acceptable bid is received.

Jose Bosingwa

The 'Flying Uni-brow' is suspect defensively and has consequently failed to live up to expectations; an acceptable bid would be well received.

Alex

The burly Brazilian is a reliable performer but never truly established himself as a first choice primarily because he is too similar to Terry.

Florent Malouda

Malouda has been one of Chelsea's standout performers in recent seasons, including their top scorer last year but does not seem to have the faith of Villas-Boas.

Salomon Kalou

A gifted but inconsistent performer, Kalou has fallen down the pecking order in recent seasons and will be allowed to leave.

Nicolas Anelka

He has 123 Prem career goals but after netting only 6 times last season and with the plethora of strikers currently at Chelsea, Anelka will be available in January.

Didier Drogba