Thibaut Courtois, who signed for the Blues in the summer for ?8million from Genk before being sent immediately out on loan to Spanish side La Liga, revealed backroom staff at Stamford Bridge are concerned over Cech's fitness after being dogged by injuries.
Hands on: There are doubts over Petr Cech's future according to his future Chelsea replacement, Thibaut Courtois
The 29-year-old Czech Republic international spent three weeks on the sidelines with a knee injury earlier this season and has to wear a protective helmet after he fractured his skull five years ago following an infamous nasty collision with Reading's Stephen Hunt.
There are fears that Cech could be hauinted further by shoulder and back problems and the rookie Belgian shot-stopper claims he is preparing to replace the goalkeeper between the sticks at Chelsea in the coming years.
'Chelsea's goalkeeping coach told me he doesn't know how much time Cech can play at the top level,' the 19-year-old told Spanish radio station Onda Cero.
'I know he has problems in his knees and on his back.
'Chelseatold me to spend two years at a club like Atletico. After that one season in an English team so I can integrate myself into the Premier League.'
Biding his time: Thibaut Courtois is loan at Atletico Madrid but targeting the Chelsea No 1 jersey
Chelsea, however, insist they have no fears over the long-term fitness of Petr Cech after new team-mate Thibaut Courtois suggested his fellow goalkeeper's days at Stamford Bridge were numbered.
Courtois, who was sent on loan to Atletico Madrid after joining from Genk, claimed the Blues' coaching staff had serious concerns about Cech's knees and back.
But a Chelsea spokesman said: 'Petr is one of the best goalkeepers in the world, always performing at the very highest levels.
'The club has no concerns at all with any aspect of Petr's game or physical condition, and we expect him to remain one of the world's best for many more years to come.'
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