Central defense is probably the single part of the team I am the most happy with. Actually, I am very happy with the goalkeeping position too. 🙂
We have a first choice CB partnership which has worked, and still works, really well. Mertesacker is no world beater, but his understanding with Koscielny is really good. I don't subscribe to the idea that Koscielny is the one doing all the heavy lifting either. Behind them we have Gabriel, who looks super talented. He seems to have everything in his locker for us to naturally phase out Mertesacker over the next two seasons. As 4th choice we have Chambers. He is 20 years old, and IMO looks like a world class talent. At his age, he isn't going to throw a tantrum and ask to leave because he will have restricted game time this season. He is also in an environment where he has really good role models to hone his game from.