The least successful campaign so far of the Roman Abramovich era had been supposed to prompt a summer of radical overhaul at Chelsea, though already it feels as if reinvention may have to wait. André Villas-Boas is assessing those at his disposal in Malaysia, with further scrutiny to come in Thailand and Hong Kong before the month is out. Yet Nicolas Anelka's intention to see out his contract at Stamford Bridge was confirmation of a trend: this team is resistant to talk of clearouts.

While it may feel perverse to suggest significant changes are needed within a squad crammed with seasoned internationals and long-established pedigree, the statistics suggest a makeover is overdue. This team have won only one league title since 2006 and watched enviously as Manchester United have re-established their vice-like grip on the Premier League since. The Double achieved in Carlo Ancelotti's first season feels more exceptional now, with even memories of regular appearances in the Champions League semi-finals starting to fade. The playing staff has been permitted to age. Villas-Boas, at 33, will seek to move some on, though that will be no easy task.

Last summer provided a more natural opportunity to trim, with Joe Cole, Michael Ballack and Juliano Belletti all out of contract and Real Madrid eager suitors for Ricardo Carvalho. This time around, the market has been less enthusiastic. With senior players, many of whom are the wrong side of 30, still under contract and enjoying hefty wages in south-west London, there is little incentive to seek an exit, and little appetite for rival clubs to lure them away. Anelka, on around £100,000 a week, announced that he would rather leave for nothing next summer, potentially for Major League Soccer, as, presumably, will José Bosingwa. "I want to stay on until the end of my contract in one year and after that we will see what happens," Anelka said. "I have never said I wanted to leave Chelsea. Even if there's an offer from someone else, I don't care because I'm seeing out my contract at the club."

After two months when the club were managerless and, effectively, in limbo when it came to identifying transfers, Villas-Boas has said he does not intend to instigate radical changes this summer. He might not have been able to even if he had tried.

The Portuguese will, like his predecessors, believe he can restore this team to the status of regular title winners and, perhaps, even make them European Cup contenders again. Yet the instability in the dugout – Villas-Boas is the fifth permanent holder of the job in under four years – has merely served to snuff out the possibility of a proper overhaul. Each manager who has come in has been confronted with a squad that, on paper at least, appears to boast quality in all areas. It would take a bold man to sanction the sale of the talismanic Didier Drogba or – and this still feels unthinkable – Frank Lampard.

Rather, the new appointment's unswerving self-belief always demands he can be the figure that truly makes the difference, extracting that little something extra from players who have too often fallen at the last in recent seasons. Such conviction does not lend itself to making swift cut-throat decisions. Neither does there appear to be much leeway at Chelsea to allow a manager time for a swathe of new recruits to bed in before flourishing. When it comes to managers, if not players, the axe tends to fall quicker at Stamford Bridge than elsewhere.

The new man in charge should, of course, benefit from the presence of David Luiz and Fernando Torres, players recruited in an eye-catching mid-season splurge who have had six months to settle and will surely now improve. Both may make a difference if fit and in form. "It's difficult when you come in for a lot of money, and you feel a lot of pressure," said Anelka, a player who has been burdened with hefty transfer fees in the past, of Torres. "You come in from another club and have new tactics, new team-mates, and you have to score and play good. Everybody knows his quality. He showed that at Liverpool. But at Chelsea we don't play the same way, there's not the same group of players and it was difficult in the beginning but now I think you will see an improvement in his game. He already looks better, and he will be better this season."

That is encouraging even when articulated by a team-mate yet, with the Spaniard understandably considered key and the club intending to secure Drogba to a one-year extension, players such as Anelka, Salomon Kalou, Florent Malouda and Daniel Sturridge – so impressive while on loan at Bolton last term – will effectively be competing as back-ups. Romelu Lukaku at Anderlecht is still coveted, with talks held over the past few days regarding a fee, but where would he realistically fit in to a squad already overflowing with forwards?

The hope within the setup will inevitably be that Villas-Boas can remind this team of their underlying qualities in the short term while promoting a process of evolution rather than revolution. There will be additions made before the window closes, and the Premier League's 25-man squad system – of which only 17 can be senior non-homegrown players – demands that some seniors will have to be shifted somehow. Yet Anelka's assertion that the managerial appointment is "a new possibility for everybody" may not necessarily be deemed healthy unless these players prove the doubters wrong.

Should they stay or should they go?

José Bosingwa

The Portugal right-back signed for £16.3m in 2008 and suffered a serious knee injury in late 2009. There have been prolonged periods of shaky form and he ended last season out of the side. Chelsea activated a clause to prolong his contract to 2012 towards the end of last season, though cynics may argue that was in the hope that they secure a fee for a 28-year-old who earns high wages at the club.

Paulo Ferreira

Another Portugal right-back, the 32-year-old joined under José Mourinho for £20m seven years ago but has become a utility player in recent seasons. He is experienced and can fill in across the backline, but he has two years to run on his contract and increasingly feels like a luxury back-up.

Mikel John Obi

At 24, the Nigerian has time to develop but he has struggled to stamp his authority on games in recent seasons with the tempo dwindling at times when he is in possession. Michael Essien's injury could thrust Mikel into the team, but there is work still to be done.

Nicolas Anelka

A £15m signing from Bolton Wanderers, Anelka had a nomadic career before settling at Stamford Bridge. He said he is happy at the club, but has moved down the pecking order since the arrival of Fernando Torres and has indicated he will run down his £100,000-a-week contract before leaving for nothing next summer.

Didier Drogba

As outlandish as it seems to suggest the time has come to move on a player who won the Premier League's golden boot in 2009-10 after scoring 29 goals, Torres may struggle to be this team's attacking focal point with such an iconic team-mate still at the club. Chelsea, fearing the prospect of witnessing the Ivorian scoring goals elsewhere, hope to keep him until 2013. Yet they might have secured a better fee for the 33-year-old this summer.