The former Liverpool and Fiorentina midfielder has agreed to a three-year deal with the Primeira Liga giants
The Swede has been linked with a return to AC Milan, while the Italy international was to rejoin Atletico Madrid - but the man in charge at Parc des Princes says neither will be sold
The Bianconeri have ceded to the midfielder's request to wear the prestigious shirt this season and his boss is now challenging him to become a club icon
Chelsea kick off their Premier League title defence against Swansea on Saturday fretting that Diego Costa's injury problems could hamper their bid to remain England's pre-eminent force.
Manchester United defender Luke Shaw believes the club's new signings will enable them to mount a sustained challenge for the Premier League title this season.