If reports are to be believed, Carlo Ancelotti, the Chelsea manager, is preparing to rest one or two key players for the visit of Portsmouth, in the wake of recent results. The Blues have gone four games without a win since beating Arsenal 3-0 at the Emirates three weeks ago, and both Michael Ballack and Ricardo Carvalho are set to be the fall-guys.

Now, not even the most ardent of Chelsea supporter would disagree with Ancelotti’s view that the side needs freshening up. The best defence in the country have conceded 10 goals in that four-game sequence and, as a unit, simply haven’t been good enough. However, Stamford Bridge regulars would be well within their rights to argue that the Italian is making an example of the wrong players.

As anybody who has watched Chelsea of late will testify, the main reason for their defensive problems has been the poor form of goalkeeper Petr Cech. There is no doubt that Cech has been a wonderful servant since joining the club in the summer of 2004, and the £7 million which the Londoners paid Rennes for his services was an astute piece of business. The Czech international’s recent performances have been heavily scrutinised, and rightly so, but while the player has certainly done enough during his time at the club to warrant a dip in form, the worry for Ancelotti is that this particular dip shows no signs of slowing down.

It hasn’t always been that way though. Cech’s arrival in SW6, while hardly met with scepticism, didn’t set any pulses racing. A relatively unknown quantity, most Blues fans believed Carlo Cudicini was good enough between the sticks to sustain a title challenge, and didn’t see the need for a replacement, but it wasn’t long before they had changed their tune. A clean-sheet on his debut – a 1-0 win against Manchester United – was a sign of things to come, and on March 5, 2005 Cech set a then new Premier League record of 1,025 minutes without conceding a goal. A string of sublime performances were instrumental in helping the club win their first title for 50 years.

Having been presented with a special award by the Premier League for breaking the record, not to mention the Golden Gloves, for keeping a record 25 clean-sheets, it was thought things couldn’t get any better. Cech, however, proved the doubters wrong, with Chelsea retaining the title the following season, conceding only 15 goals throughout the whole campaign – another record.

Many of his critics point to an October evening back in 2006 as the most significant reason for Cech’s fall from grace. In a Premier League encounter at the Madejski Stadium, against Reading, Royals’ midfielder Stephen Hunt challenged Cech early in the game, leading with his knee. The tackle appeared unnecessary, with the chances of Hunt winning the ball pretty slim, and as he collided with the goalie, Hunt’s knee smashed into his head. Cech was rushed to hospital, and underwent surgery for a depressed skull fracture, and doctors said it almost cost him his life.

The challenge, somewhat predictably, sparked outrage, and Chelsea manager at the time, Josė Mourinho was particularly scathing in his criticism of Hunt, referee Mike Riley and the South Central Ambulance Service. After three months out, Cech returned to the Chelsea goal for the 2-0 defeat against Liverpool at Anfield in January 2007 wearing a protective headguard. Following that fixture, he reverted to type, embarking on a run that saw him go 810 minutes without conceding a goal, and culminating in him being awarded the Player of the Month Award for April – the first goalkeeper to win the award since Tim Flowers in 2000.

What made Cech so dominant during those times was the way in which he commanded his penalty-area. He was, and still is, a fantastic shot-stopper, but the problems Chelsea have been suffering from of late stem from his inability to judge whether or not to come for high balls pumped into the danger zone. Every team that has won the league have been built on rock-solid defences.  Chelsea, during their back-to-back triumphs, along with both Manchester United and Arsenal in their respective periods of dominance, have had some mesmeric attacking talent at their disposal but, ultimately, they wouldn’t have been able to scale such dizzy-heights without a reliable defence.

With games coming up against both Portsmouth and West Ham, Chelsea will feel they should be taking maximum points without too many problems. This, then, could be the ideal time for the manager to give Petr Cech a rest, and take him out of the spotlight for a couple of weeks. Both Hilario and Ross Turnbull are more than capable of filling in for a few weeks, and a run of games would do Turnbull in particular the world of good.

Ancelotti has chosen to stand by Cech up to this point, publicly backing him when the goalie has clearly been culpable. Whether or not he feels dropping Cech could further chip away at the already brittle confidence levels of his keeper only he knows, but any further mistakes, particularly at such a crucial stage of the season, would leave him with no choice.

The 2-1 defeat at Manchester City a couple of weeks ago was a big blow for the Blues, and while they certainly weren’t at their best, they could have left Eastlands with at least a point had it not been for Cech’s bad positioning for Carlos Tevez’s winning goal. Similarly, earlier in the season, only Florent Malouda’s  last-minute strike spared Chelsea’s blushes at the Britannia Stadium against Stoke City, after a horrible Cech blunder allowed Abdoulaye Faye to head the home side in front.

The notoriously difficult festive period could go a long way to deciding the fate of both Cech, and Chelsea. A few clean-sheets, coupled with some decent performances, should see the career obiturary writers putting their laptops away for the time being. Any further mistakes, however, and both will be hitting the headlines for all the wrong reasons.

Any player that has picked up the award for best goalkeeper in the Champions League on three separate occasions undoubtedly still has a great deal to offer, and don’t bet against Cech, so often the butt of opposing supporters’ jokes, with regards to the protective headguard, having the last laugh.