Chelsea have held extensive talks to sign the 19-year-old this summer and two offers have already been rejected by Inter but the third, worth £12m, is likely to be accepted.
It had been thought that Chelsea might miss out due to interest from French club Nice, who would be more likely to offer Casadei regular playing time, but The Guardian are now reporting that the Blues are set to win the race for his signature.
Casadei is yet to make his senior debut for Inter but the midfielder is widely regarded as one of the brightest young prospects in Italy.
Inter had been holding out for a £20m fee for Casadei and also wanted the option to sign him back from Chelsea in the next few years.
But Chelsea are unwilling to allow Inter to have a buy back clause as they view Casadei as a key part of their future plans.
Casadei has been extensively scouted by Chelsea’s academy chief Neil Bath and the club are hopeful of securing a deal after the £20m signing of Aston Villa midfielder Carney Chukwuemeka earlier in the window.
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When asked about Casadei’s future this summer, Inter’s CEO Beppe Marotta said: ‘Today he’s a young talent. He still has a long way to go before he can become a top player, but we’re very proud to have him with us.
‘He’s training with the first team, he’s proving to be at a very good level.
‘Right now I can only talk about him in positive terms as he’s above average for his age, and after that a lot depends on him.