Nathan Ake is to replace Cahill on the left of defence against Spurs.

Antonio Conte is seeking a new captain for Chelsea’s FA Cup semi-final with Tottenham on Saturday as John Terry faces being a substitute at best despite the enforced absence of Gary Cahill.

Cahill has been a key figure in Chelsea’s defence this season, playing in a three-man defensive unit with Cesar Azpilicueta and David Luiz, but the on-field skipper is out of the Wembley tie following gastroenteritis.

Terry has not started in the Premier League – where Chelsea hold a four-point lead over Spurs with six games remaining – since September.

Conte says Cahill was sent to hospital by the doctor for checks. It is not a serious problem but it will be difficult to play tomorrow. #CFC — Chelsea FC (@ChelseaFC) April 21, 2017

Former England international Terry this week announced his 22-year stay at Chelsea will end. Five of the 36-year-old’s 14 trophies were FA Cup wins.

Terry, who made his 713th and most recent appearance in the fifth-round win at Wolves in February, cited a wish to keep playing for his decision to leave Stamford Bridge at the end of this season, Conte said.

Nathan Ake is to replace Cahill on the left of defence against Spurs, with Conte insisting Terry is more suited to the central position in the back three, where Luiz is first choice.

“There is only one captain in Chelsea now and it is John Terry, if he plays or doesn’t play,” Conte said.

Chelsea boss Antonio Conte (Mike Egerton/PA)

“(But) we have to find a new captain, and this is another problem that I have to solve. In this system the right position (for Terry) is in the middle of the three central defenders.

“If something happens to David Luiz, for sure the player with the right characteristics to play in this position is John.

“(But) in this case I think for this position Ake has the right characteristic to be the substitute for Gary.”

Kurt Zouma is Azpilicueta’s deputy, Conte said.

Conte calls Tottenham a great power in English football. He says it is the right moment for them to stop feeling the underdog. #CFC — Chelsea FC (@ChelseaFC) April 21, 2017

Conte insisted the result of the FA Cup clash was irrelevant to the Premier League – “I don’t think if one team wins or loses it can affect the other competition,” he said – but rebuked Mauricio Pochettino for apparently preparing an “excuse”.

Pochettino on Thursday said his side were underdogs, but Conte disagrees.

“There is a moment you have to finish considering yourself an underdog. I think this is the right moment,” the Italian said.

“Tottenham now is a really great power in English football. This is the third year for them (under Pochettino) and I think it’s the right moment to finish (talking about being) considered (an) underdog and to find his excuse.”