Jose Mourinho says his star striker Diego Costa is fully fit

Diego Costa is the second highest goalscorer this season after Sergio Aguero

London, Nov 22: Jose Mourinho has declared Diego Costa finally free of the hamstring injury that has dogged his Chelsea career, but admitted to concerns about how he would cope with their "incredible marathon" of games for the rest of 2014.

Costa is expected to start Saturday's game with West Bromwich Albion after being excused from Spain duty during the international break in order to fully address a problem that has blighted his otherwise explosive start to life in English football, reports Daily Telegraph.

But his manager admitted a run of 12 matches in less than six weeks would be a culture shock for his star striker, who is used to having Christmas off.

"Now we are going to have a period that is new for him. I believe the Christmas period for players doing it for the first time in their careers is more difficult," he said.

"The English players or those who have been here for many years, are more physically and mentally adapted and prepared to cope with the special incredible marathon of football we face."

Mourinho revealed he had already warned Costa, who has scored 10 goals in nine Premier League games, of the unique demands of the festive period.

"We spoke yesterday about it but we feel he is free of his old injury," he said, before pointing out that the 26-year-old was one yellow card away from a suspension.