The Brazilian centre back was overshadowed on deadline day by a certain Fernando Torres, but he went on to outshine the Spaniard anyway both on the goals chart and in terms of individual performances. The technically-excellent volley against Manchester United especially will go down as one of the highlights in an otherwise disappointing season for the London club, but it was the return fixture at Old Trafford that really showed us what we have on our hands with the wild-haired defender.

So what can he do? He is a good defender. His performance against Manchester City epitomizes this, making eight interceptions and four tackles, 2 of which were deep within the penalty box, and he is also an outlet in attack, as he showed with the opening goal from the set-piece. He is also versatile, adapting to numerous positions already in his time at Chelsea. Ancelotti suggested that Luiz would make a good holding midfielder when the Brazilian signed, and he played there and at right-back on his full debut against Fulham.

But there are always negatives. His exuberant enthusiasm has lead to many wild tackles, most notably the penalty he gave away against Fulham and the desperate lunge on Wayne Rooney against Manchester United. He has obvious defensive deficiencies in his game. Too often we see his positioning is off-target; on the run side of the man or not tracking goalside. The two most obvious examples are Jonathon Walters for Stoke and Javier Hernandez for Manchester United. Also, he often has a tendency to drift too wide and leave the centre exposed.

As we take these pros and cons of David Luiz, it is time to ask the question: where does the Brazilian fit into Chelsea’s system to get the best out of his potential?

Centre-back

The most obvious, and rational, of the positions available: the one he currently occupies. He has extensive experience here, having played it commandingly alongside Luisao for Benfica in their surge to the Portuguese league title last season, a partnership that conceded just twenty goals in the league alone. Luiz made his name as an ever present defender, and despite what some Chelsea fans believe, he was renowned for his defensive prowess rather than his attack – scoring just four goals for Benfica in seventy-two performances: only two more than he already has for Chelsea in twelve.

Playing at centre-back means that Alex is dropped out of the side and it’s very easy to forget what a difference Alex makes to the side; he started every game under Guus Hiddink and this was matched with a remarkable overturn in the defence. Alex’s experience at the Premier League level was noticeable in the differences between his and Luiz’s performance against Manchester United. Such depth in centreback is unparallel at most major clubs, and it’s not exactly something to rue; having to choose between two quality Brazilian centre-backs.

So if we have the dilemma of choosing either Luiz or Alex, then does it make sense to shift the more flexible and versatile player into another position?

Left-back

Luiz played here in his first season on loan at Benfica. His tendency to get forward and join the attack, and solid ball-playing technique are attributes that contribute to this versatility, and he played a majority of his 2008/2009 in the position in favour of the Portugese international Jorge Riberio. However, he does not have the attack-minded mentality of Ashley Cole which has proven to be such an asset on the left hand side, and any replacement there would weaken the side; for Cole’s contribution is best summed up by his peers’ decision to name him their Players’ Player for 2010/11.

In this ideal, it makes more sense for David Luiz to become the Ivanovic of Chelsea’s left hand side. As with the Serbian, having a defender that has the adaptability to rotate positions is a strong asset in any line up.

Left back is an option; but unlikely due to the depth and starting quality the club already has in that position.

Defensive midfield

Luiz began his trade playing in front of his backs until the age of fifteen where he was moved further down the field. Now as he approaches that ten-year anniversary, is it nigh time to make a switch?  Carlo Ancelotti agreed as much when Luiz first signed back in January, where he covered the idea of Luiz as a midfielder:

On the cover it seems this would be a sensible move. Luiz is comfortable on the ball, composed with his passes and has a keen eye for goal. He would be a more dynamic version of John Obi Mikel, but we must be careful not to take that as a positive. The Brazilian’s high-tempo and energetic game has led to some rash decision making, evidence being the penalty conceded against Fulham. This kind of enthusiasm, while great on one flipside, has negative repercussions if it, for example, leads to a yellow card, and Luiz must then tone his game in order to risk not being sent off. Having a defensive midfielder on a yellow card is a dangerous thing in football: it gives the opposing, more creative midfielder more licence to roam, as the marker is less physical in his approach.

A cracking eye for goal is something many Chelsea fans call for from Mikel – does Luiz add this attribute to the holding midfielder’s game? Yes, and it would be a fascinating performance to observe, but the rashness mentioned above would relegate his game.

Sweeper

On Twitter many Chelsea fans see Luiz as the answer to an very modern tactical question: can the sweeper return to prominence?

Luiz has the attributes to perform in such a position. However, a sweeper requires a system set out around himself, and such a drastic change in setup is unlikely from Ancelotti at such a crucial point in his tenure. Should the Italian be removed from his post, then a forward-thinking coach might seize on the opportunity.

Playing a sweeper would certainly give players like Ashley Cole and, if reports are to be believed, Gregory Van Der Wiel licence to roam forward. It would give the side more options to play the ball out of defence – think Barcelona, the club Abramovich wishes to emulate in London, and it also allows for flexibility in other areas of the pitch, in terms of the midfielders and strikers deployed.

However, we must also rememeber that Luiz is first and fore mostly, a centre-back. It is indeed, on current evidence, his strongest position, and we must always remember that it has only been five months into his Chelsea career. At 24, he has a big future ahead of him, and blimps like Fulham, Birmingham, Stoke and Manchester United will be learning curves as he adapts. I myself preached patience with Ramires, and now we must exorcise this same faith with a new Brazilian. He has the tools, as Ancelotti wholeheartedly agrees, to become the best defender in the world. His future in Chelsea’s system is the key to unlocking this potential.

Discuss Luiz’s Chelsea future on Twitter at @cfcreport