You could always buy him and throw him in defensive mid if you use one?
The guy is a dominant center back but even more dominant between midfield and defense as an anchorman, his skills are perfect for that.
For center back though, you do not need him and he will only cut into the playing time of Vermaelen, Kos and Mertesacker and that will mean someone will end up being pissed off. And to sign a great defender for 4th choice is a bit too much on the nutty side.
If you need a good/great DM then he can be your man, for CB you would have to share time between 4 guys.
I decided to get Kompany and flog off Mertesacker to Juventus as he was the least consistent out of him and Kos last season. I could play him as DM, but I'm happy with Song atm, and I've got two good young back-ups in Coquelin and Frimpong.