There seem to be two prevailing opinions around Arsenal's deadline day signing of Mesut zil. The first, from detractors and generally fans of rival teams, is that Arsenal may well have bought themselves a world class player, but they have completely ignored their more pressing needs; namely a striker, a centre back and a defensive midfielder. The second, held mostly by Arsenal fans and those blinded by the stellar nature of the signing, is that a big name player, any big name player, is exactly what Arsenal needed to put themselves back on the map and announce their arrival as major players in world football again. Whilst there is merit in both opinions, there is one element of the first that is invalid. Arsenal do not need a defensive midfielder. Why? Well, to start off with, they've got one - Mathieu Flamini. He may not have cost £42 million, or even £42, but he is predominantly a holding midfielder, who has very little ambition to get himself across the halfway line. He's only got three caps for France (the last in 2008), no other clubs showed any significant interest in signing him and there are probably twenty or thirty players in the world who have a stronger reputation playing in that position than he does, but he is still a defensive midfielder of some experience and who Wenger knows well. The most important reason, however, is that Arsenal no longer play with a single deep central midfielder. The system or formation that has emerged at the club over the last few seasons, since the switch to a 4-5-1/4-3-3, has three central midfielders; one whose role is almost completely devoted to attacking (generally Cazorla, but surely zil henceforth), and two who sit deeper playing as a double pivot. In this shared role, the two players in the pivot position cover both attacking and defensive duties and they can adjust their tendencies as the situation requires. Wenger, in stocking his squad full of central midfielders of different types, can also mix and match depending on the situation. Wilshere, Ramsey and Diaby (when available) can play as box to box midfielders, getting stuck in at the back, but also driving forward safe in the knowledge that they haven't left a hole. Arteta is more suited to retaining possession and playing the simple ball, and can be relied upon to hold his defensive position. Flamini is an even more disciplined and less creative version of Arteta. Rosicky, now marginalised in the more attacking positions but whose experience is valuable, can play a hybrid box to box / attacking midfielder role against the lesser teams where shape, discipline and organisation ought to be sufficient to nullify any threat. zil and Cazorla could do the same if required, and Oxlade-Chamberlain also seems to be developing in the box to box role whilst still predominantly a wide player. With this system, Arsenal have everything they need to have a creative, but solid and robust midfield. If the balance of the team is wrong, there are plenty of available options to make adjustments. The strategy is genius in its simplicity, they can have an additional creative player on the pitch, without any great loss of defensive solidity, provided the two players in the double pivot show the necessary awareness, discipline, energy and communication to pull it off. It also allows protection of some of the more fragile players in the team through squad rotation. Ultimately, there are still two glaring holes in Arsenal's squad, most significantly the lack of a first class alternative to Giroud, and less worryingly the absence of a dedicated fourth choice centre back. But what Arsenal most definately don't need is a one dimensional, waste of half a position, dedicated defensive midfielder.