Brazilian defender Alex has penned a new deal with Chelsea, keeping him at Stamford Bridge until 2013, the Premiership leaders said. "I am very happy to start again to train and feel no pain, and to sign for four more years," the 27-year-old told Chelsea's official website. "It was easy to decide to sign and now I hope to get back to playing well. My condition now is so-so. I think in two more weeks I am 100 per cent and can play without a problem." Alex has yet to play for Chelsea this season as he was nursing a serious groin injury before resuming full training this week. The former PSV Eindhoven center-half is the second Chelsea player to seal a new contract this week after Ivory Coast winger Salomon Kalou.