Chelsea will only discover on Thursday the extent of John Terry's injury after the skipper lasted just 15 minutes of Tuesday's Champions League defeat to Shakhtar Donetsk.The former England international limped off in the first-half of their Group E encounter with a recurrence of the calf injury that ruled him out of the Three Lions' World Cup qualifiers against San Marino and Poland.The defender will now undergo scans on Thursday, with the 34-year-old hoping to shrug off the complaint ahead of this weekend's mouth-watering Premier League tie against Manchester United.Chelsea manager Roberto di Matteo said: "It's basically a recurrence of an old injury."He was training with us fine and there were no alarm bells before the game. He was in good condition to play."