The Spain international, a £32m signing from Atlético Madrid this summer, will undergo further tests at Cobham and while the initial prognosis appeared grim, there are hopes the injury will not prove as severe as first feared.
Although Chelsea have not written off his chances of featuring at Everton on Saturday, even if the injury rules the Brazil-born forward out for the forseeable future they may sanction Fernando Torres’s mooted loan move to Milan.
From the Guardian.
Not buying this Costa ''injury'', classic Mourinho mind games. It deflects the attention off him if he isn't fully fit and doesn't play well. Plus, Everton away is one of the toughest fixtures on the Premier League calendar, I doubt something like this would be coming out if they were at home to QPR.