Diego Costa's hamstrings are picking up right where they left off at the end of last season, causing trouble.
Chelsea FC (@ChelseaFC) August 2, 2015
The striker had gotten the all clear on Friday from Jose Mourinho, but as it would appear, the hamstrings weren't quite ready to go. Costa picked up the injury just a few days ago in the friendly against Barcelona. His immediate withdrawal seemed more precautionary than anything else at the time.
While this also doesn't sound too bad, hamstring injuries can drag on for an annoyingly long time even without ever looking al that serious. Fortunately, Loic Remy is uninjured, so we won't have to find out just what Falcao would bring to the table as a starter in a real game just yet.