There's clearly a difference but as I say, if he's competing with three other centre backs he isn't going to get a lot of game time. He'll get some because of injuries and rotations but if we try him at DM in pre-season then depending on how he does it's another potential position he can perform a role in. I've seen a lot of him as well and I feel as though I'm a decent judge of a player - he's very very good in possession and he isn't afraid to pass the ball forwards either. Combine that with his composure and excellent ability to read the game (albeit as a centre back) and it's worth trying him out as a DM considering our other option in that role is hardly setting the world alight.
If he can get a few games more by being able to play in that position then I think it's a good thing. As I said, when Kompany arrived and was played at DM he was often sloppy in possession and if someone had have told me he'd go on to be one of the best centre backs in the world I'd have laughed. Denayer has so much composure and intelligence for a young player and I want him to get as much time on the pitch as possible. I'm not talking about using him like the rags use Jones and playing him everywhere and anywhere, but it's worth trying him in pre-season if it means more game time. I don't think playing as a DM does any harm to a player who wants to play CB, it gives him an opportunity to get used to the pace of the league without being left in the firing line - you can get away with the odd poor positioning etc at DM more than you can at CB.