Todd Boehly confessed one of his early expensive Chelsea recruits struggled to cope with the pace of the Premier League.

The American’s ambitious recruitment drive has seen his Clearlake consortium spend over a £1billion on new talent with the focus largely centering on bringing the best young talent in the world to Stamford Bridge.

One of his more experienced signings, Kalidou Koulibaly, was supposed to be a ready made solution to Chelsea’s defensive issues.

The former Napoli captain had been coveted by the Blues by a succession of Chelsea managers and when Thomas Tuchel finally secured the services of the Senegal international, it was anticipated that Koulibaly would play a central role in the rebuilding project.

Instead, Koulibaly struggled from the get-go and never recovered from a particularly inept display against Leeds United when he was sent-off on what was only his third game for the club.

Indeed, after just 20 Premier League appearances for Chelsea, he was sold to Al-Hilal last summer with Boehly forced to accept a 50% loss on his investment.

The Chelsea owner insists he maintains a great relationship with his now former player but revealed the 32-year-old couldn’t believe the difference between the English top flight and Serie A where he had spent the peak years of his career.

‘There’s no bigger sport in the world,’ Boehly said. ‘When you think about just the size and scale of European football, it’s just mind-numbing and there’s no better league in the world in the Premier League.

‘If you look at how these guys play, the speed with which they play the game. One of my players who I had a great relationship with is Kalidou Koulibaly.

‘Koulibaly came over from Serie A (where he played for Napoli) and he told me one time, ‘In Serie A, I get to think and then run but in the Premier League, I have to run while I think, and I’m still adjusting to that’.’

Chelsea have subsequently invested fortunes on a host of new defenders, including the likes of Benoit Badiashile, Axel Disasi and Wesley Fofana.

Despite those investments, the Blues are likely to sign at least one new centre-half this summer following confirmation of Thiago Silva’s departure.

In a video to Chelsea fans confirming his exit last week, Thiago said: ‘Chelsea means a lot to me. I came here with the intention of only staying for a year and it ended up being four years. Not just for me but for my family, too.

‘My sons play for Chelsea so it’s a source of great pride to be a part of the Chelsea family – literally because my sons are here. I hope they can continue their careers here at this victorious club that many players wish to be part of.