Bertrand Traore
Bertrand Traore missed Burkino Faso's loss on SaturdayGetty

Chelsea forward Bertrand Traore missed Burkina Faso's African Cup of Nations qualifier defeat to Botswana with a mysterious hip injury. Traore, who was retained as part of the Blues first team by manager Jose Mourinho, after being awarded a work permit earlier in the year, was left out of the Burkina Faso squad that travelled to Francistown on Saturday.

Manager Gernot Rohr did state the knock isn't considered a major problem. "Bertrand had to withdraw due to his hip injury," Rohr was quoted as saying by African Football, speaking before Saturday's game. "It is not very serious, but it is painful enough to prevent him from playing."

Traore, 20, has been named in both Chelsea's Premier League and Champions League squads for this season, alongside fellow attacking starlet Kenedy.

Chelsea have suffered from a handful of injury problems in their disappointing start to the 2015-2016 season. Defender Gary Cahill broke his nose towards the end of the club's pre-season campaign and took blows to the face again in the Community Shield defeat to Arsenal and the league loss at Manchester City.

Diego Costa meanwhile has been beset by the hamstring injuries that plagued him last season, while Brazil international Oscar has not played since the opening day of the season against Swansea City.

Fitness problems have not helped the club during their slow start to the season. Jose Mourinho's side are already seven points behind leaders Manchester City, having lost two of their opening four games of the season to Manuel Pellegrini's side and Crystal Palace.

The club face another stern test next Saturday when they talk on Everton at Goodison Park, a game that will have an added spark after Chelsea's failed pursuit of Toffees defender John Stones during the summer transfer window.