With the deadline set, Arsenal now has Sokratis, Shkodran Mustafi, Konstantinos Mavropanos and Shkodran Mustafi in central form. Someone is really comfortable with that group? The transfer window is closed. On a fairly quiet day, Arsenal completed only one move of any kind: the £ 4 million sale of Lucas Perez. It was no surprise to anyone. If there were any repayments on this day often fueled by panic, then it would have been middle-half. But there was not. That leaves Unai Emery with only four fit midfielders to start the season – Calum Chambers was, strangely, unexpectedly and perhaps a little foolishly lent to Fulham for the season, while Laurent Koscielny will not be back in action until December as soon as possible. More from Pain in the Arsenal: these four central defenders in form are: Sokratis Papastathapoulos, signed for around £ 17 million this summer; Shkodran Mustafi, a player who has suffered a tumultuous first two seasons in the north of London, but shows a promise; and two young prospects in Rob Holding and Konstantinos Mavropanos, on which much will be placed, especially in the first part of the year. It is not a convincing quartet. Mustafi and Sokratis will be the starters. They are the most experienced of the four, with Mustafi the only one to be familiar with the regular start of the Premier League, and Holding and Mavropanos will be in contention for the third central position and both will probably start in the national cup and matches of Europa League group. One of the two will be the first reserve in the Premier League in case of injury or suspension between today and the return of Koscielny. And let's talk about Koscielny's return. There is no guarantee that it will actually return when it does. A thirty-two year old (will turn 23 in September), whose body has worked for many years, recovering from a broken Achille, a notoriously difficult and unpleasant injury, returning to the team at the climax of the season – during the manic Christmas meetings. This is not your average rehabilitation process. Do you want to hear your voice? Join the Pain In The Arsenal team! Write for us! As we have seen two seasons ago with Per Mertesacker, who was a younger year than Koscielny is now and has not constantly struggled with injuries like the French, when he tried to recover from an injury knee, it was not until February / March that he was able to start. Or as we have seen with Santi Cazorla and his ankle problem. Older players struggle to get back from injury in the quickest and most complete way. It is not inconceivable that Arsenal can survive for the next season with the four central defenders that they currently possess and are in good shape. I'll be honest, it's not a situation where I feel comfortable. In fact, I ask, is someone really comfortable with that situation? I would suggest that he is a bit naive or too optimistic to be like that. Next: Arsenal Vs Manchester City: 5 Key Players to Watch It remains to be seen how all this takes place. Mavropanos could take the important steps that he mentioned. Sokratis could shine in a new championship like it has never done before. Mustafi could finally deliver his skills. Koscielny could make a remarkable recovery. But this is a lot of things for the Gunners simply to be decent in the position, no matter the elite. This is really an uncomfortable situation.