London - Chelsea manager Jose Mourinho said Diego Costa was likely to be out for at least two weeks after his hamstring problem resurfaced during Saturday's 2-1 win over Stoke City.
The Brazil-born Spain striker, 26, pulled up 10 minutes after coming on as a half-time substitute for Oscar at Stamford Bridge, with the score 1-1.
Didier Drogba came on as a hobbling Costa - Chelsea's top scorer this season with 20 goals - was escorted off the pitch and down the tunnel by members of the club's medical staff.