Chelsea have signed Serbia midfielder Nemanja Matic on a four-year contract from Slovak team MFK Kosice, the Premier League club said on Tuesday.
The 21-year-old, who has two caps, will not be available immediately because he is recovering from a broken metatarsal suffered at the European Under-21 Championships in June.
Matic said he was looking forward to joining up with fellow Serb Branislav Ivanovic at Stamford Bridge.
"I play with Branislav in the national team and have spoken to him about Chelsea," Matic, who had a trial with Middlesbrough last season, told Chelsea's website (www.chelseafc.com).
Chelsea said earlier on Tuesday that Peru striker Claudio Pizarro had joined Werder Bremen on a permanent basis after spending last season on loan at the Bundesliga club.