Despite Rafa says it's a signing for the first team it might be a progressive introduction to the first team, a bit like Agger yesteryear.
I'd like to clarify whether he's an attacking midfielder as I've read I think in the Rafa quotes, or a defensive midfielder as I've read to other posters and in the article in portuguese upper in this thread. A volante, as far as I can tell, is not an attacking midfielder.
The article in portuguese highlights that the negotiation have been kept in secret, and things rushed up after a recent muscle injury of the player. The article highlights aswell, that it's the most expensive player sold from that league since Rochemback went to Barcelona back in 2001.
To be honest, it's an important amount, hope he's good. Or at least better than Rochemback. A good example to remember of how very promising players might not confirm their expectations.
P.S. I thought that I read somewhere when I browsed quickly the thread hours ago that he was attacking mid, but I've re-read it and I was wrong. Rafa has stated he wants Alonso and Mascherano I think, so this news is great, hopefully next season we'll have a deep-competitive squad RIGHT FROM THE START of the season, and we don't have to look for desperate reinforcements in winter.