It should be clear as day to everyone by now, that Masch isn't a DM anymore, and most likely won't ever be again. At least not for us. Masch just doesn't have the basic skill set that's required for a DM in our system. Whether Song has this is probably debatable, but he's a much better fit, on paper at least, than Masch is.
About Masch, I agree we won't see him at DM for Barca anymore. But the reason is not because he can't be a Barca DM. He is going to be starting at CB at least 40 games a year, so he is just not available for any other job. He will play more CB than Puyol from now on, and quite possibly also more than Pique. We'll see who starts in the biggest games. All three have huge rolls to play, I don't think Tito wants to rotate in any other CBs.
The coaching staff thinks Song is better at DM than Keita, that's why Busquets is finally getting enough rest this year. If necessary, I think Tito will go with Adriano or Busquets at CB before Song. I think Song's additional job is more likely to be at the other midfield positions. He can shoot, he can dribble around and through defenders to create scoring chances, things that Busquets just does not offer. Like Keita, he can play the last 30 minutes for Xavi or Iniesta when the team has a good lead.
The team has looked bad advancing the ball from the back recently when Busquets has been off the field. Most of these times, other superstars have also been off the field, so it's not all been on Song. Even with his weak scoring and goal creating, I put Busquets #1 in the world at DM, so his backup is always going to be a big step down.
