Diego Costa
Costa scored 20 goals last season but reports have emerged suggesting he is unhappy in EnglandGetty Images

Chelsea striker Diego Costa has been urged to remain in the Premier League despite reports indicating the Spain international is unhappy with life in West London.

Reports have emerged from the 26-year-old's homeland indicating that despite netting 20 goals and winning the Premier League and League Cup double in his maiden season in English football, Costa has failed to adapt to his new surroundings.

The food, the language and the English weather are contributing to Costa's desire to return to former club Atletico Madrid however any departure is regarded as unlikely given his importance to Chelsea after he fired the club to two pieces of silverware.

Costa's first season at Chelsea was also dominated by injury, which saw him miss several weeks of the campaign with a hamstring problem while a series of disciplinary problems ensured he was constantly under the spotlight.

Mourinho labelled the reporting of Costa's misdemeanours as a "campaign" against Chelsea and ex-Blues forward Gianluca Vialli believes such attention may have contributed to the player's dissatisfaction.

"I think he will eventually fall in love with London and the Premier League because it happens to everyone soon," the 50-year-old said. "I don't see why it shouldn't happen to Diego Costa.

"Maybe it was a bit tough, all the controversies surrounding his behaviour on the pitch and some of his performances but I think he will eventually fall in love with London and stay for a long time because I think he is an exceptional player."

A defender, a midfielder and a striker are on Mourinho's transfer wishlist this summer after the Portuguese boss confirmed his targets for the upcoming summer transfer window.

Didier Drogba is the sole departure from Chelsea since the end of the season but high-profile exits have dominated previous windows, with Juan Mata, David Luiz and Andre Schurrle having left for £35m ($54m), £50m and £24m respectively.

And Vialli believes that Chelsea should continue the trend of selling big name players for hefty fees, while a replacement for the departing Drogba should be a priority for the Premier League champions.

"Keep selling incredibly well like he did in the past with [Juan] Mata and David Luiz for example and other players and use the money wisely to sign players," he said.

"I think Chelsea have been extremely good in the last two or three seasons at looking after the finances of the club. Selling very well, making money and spending the money wisely and while doing that strengthening the side considerably.

"I don't see any particular weaknesses. They have a very talented starting 11, the squad is quite strong. Drogba is leaving so there might be an opportunity to sign another excellent striker to play with or instead of Diego Costa.

"Mourinho at some stage will have to think about the future without John Terry but at the moment he is still one of the top defenders and leaders in the Premier League.

"I don't see weakness but it will also be down to Mourinho to understand whether all these great players have got the motivation and determination and focus to do well."

Gianluca Vialli was speaking at the Sport Industry Breakfast Club