The simple answer is absolutely. A more dignified answer revolves around the basis of three elements.
Firstly, Arsenals currently possess their best centre back partnership since Sol Campbell and Kolo Toure of the Invincibles. Over the years their back-ups have always been below par and weren’t worthy of wearing the Arsenal badge. Players such as Pascal Cygan, Phillipe Senderos, Johan Djourou, Sebastian Squillaci. I’ll even go as far as saying if Per Mertesacker and Laurent Koscielny in their current form were part of the 2010/11 Arsenal side, they would’ve fought for the title till the end of the season. The point is, even if you have a solid partnership, the back up have to be of the necessary quality to come in and perform the task required. Besides Thomas Vermaelen, who I’ll discuss in a bit more detail later on, Arsenal do not have any other centre backs who can play every week.
Yes we do have a talented list of young centre backs including Isaac Hayden, Sami Ajayi, Julio Pleguezuelo and Stefan O’Connor but they’re too inexperienced to be thrust into the spotlight if one of our main centre backs get an injury. They should definitely be given opportunities next season, in which I’m sure they’ll impress as they look to be future world class players. I’d be the first one to laud Arsene Wenger for allowing such young players to prove their worth for the club rather than never letting them fulfill their potentials in the reserves.
Secondly, with the imminent departure of Bacary Sagna who deputised as a centre back whilst two of the three main ones were out, this now means that if we don’t sign anyone, then one of the reserves players will have to come in. It also seems likely that club captain Thomas Vermaelen will depart. This potentially means Arsenal will have to sign two players for the position. I’m sure Wenger will try his best to keep him in order to prevent the need for more than one central defensive signing. As we’ve seen in the past with Per and Koscielny, new players take at least one season to get used to the Premier League standard. To be quite honest, Arsenal need an upgrade on Vermaelen. He was on the bench for the most of the season but to his credit, whenever he was called upon he showed glimpses of his best form. The captaincy will almost definitely be taken from him so maybe then he can focus on solely on his defensive duties.
Thirdly, Mertesacker and Koscielny are not young players. As defenders they can play at the highest level till the age of 33 to 35. But Arsenal must plan for the future whilst they have such great talent to mould the next generation. Any talented defender we bring in will learn all the skills and wits of being a world class defender. If Vermaelen stays, Wenger must bring in a young first team quality centre back. If he leaves then maybe an older experienced player to replace him.
A couple examples for the young centre back could be:
Aymeric Laporte, Kyriakos Papadopoulos, Cheikhou Kouyaté
For older players: Joleon Lescott, Carles Puyol, Rio Ferdinand