Graeme Souness believes Chelsea will have to bring in a quality striker to replace Didier Drogba this summer.

The veteran will depart Stamford Bridge after helping the Blues clinch the Premier League title but his vacancy will need to be filled appropriately if Jose Mourinho's side is to kick on and defend this season's crown.

"Didier Drogba found life tough when he got his games towards the end of the season," said Souness on Sky Sports. "He found it a difficult league to play in at his age.

"So with him going I think they need to get another striker and I'm sure he's going to address that.

"With Diego Costa, is his hamstring fully cleared up? He arrived with it and it seemed to be a problem for him throughout the season.

"When he was playing early on, he was doing a real job for them. But they will add."