Costa's dodgy hamstrings concern Jose
Perhaps there might just be a chink in Chelsea's seemingly impenetrable armour.
While the Blues have started the season in blistering fashion thanks largely in part to Diego Costa's goal, Jose Mourinho has revealed that the Spanish goal machine isn't capable of playing three games a week becuase of his dodgy hamstrings.
Despite scoring a hat-trick against Swansea in the English Premier League on Saturday, the 25-year-old began Chelsea's Champions League opener against Schalke on the bench as the Blues were held to a 1-1 draw.
Not enough recovery time
Mourinho said: "Costa has a problem. If he has one week to let the muscle recover he can start a game. Playing on Saturday, three days is not enough for him to recover.
"It was not to protect for the game Sunday (at Manchester City) it was because today he was not in condition to start the game."
Costa has a well-documented history of problems when it comes to his hamstrings.
The striker was substituted during the Champions League final in May with a hamstring injury as his former team Atletico Madrid fell 4-1 to city rivals Real Madrid.
The Brazil-born player then had an ineffective World Cup campaign as Spain crashed out in the group stages and later suffered a hamstring problem while on international duty earlier this month.
Chelsea might still be favourites to win the EPL, but knowing that their star striker has a real weakness might just give opposing teams some hope just yet.
Source: PA Sport