Many Chelsea fans thought that Oriol Romeu was going to make the team as a backup to Nemanja Matic this season. It made a certain amount of sense: he was impressive in pre-season and had just signed a new three-year deal with the club. His season long loan to Stuttgart, then, comes as something as a surprise, but the club has now confirmed that it's a done deal, and that he'll be spending next year in the Bundesliga.
This might be something of a last chance for Romeu, who despite looking good early in his Chelsea career has been massively inconsistent, falling out of favour with Roberto Di Matteo and then picking up a serious knee injury when he had a chance to impress later that year. He didn't do particularly well at Valencia (although that's not a surprise after recovering from an ACL injury), so a good spell in Germany will do his stock a world of good.
As for Chelsea, this leaves them with John Obi Mikel as the only real backup for Matic. Is there more to come in midfield, or is Jose Mourinho fine with what he has? Romeu's loan also reduces the number non-homegrown players in the squad by one.