The Daily Star says Blues boss Jose Mourinho wants to strengthen his defence with a move for highly-rated French-born Moroccan international.
The west Londoners switched their attention to Benatia after Real Madrid indicated French defender Raphael Varane was not for sale, and with Atletico Madrid star Joao Miranda opting to remain in Spain.
Mourinho has yet to replace Brazilian David Luiz, who joined PSG this summer for £50m.
Chelsea will have to sell at least one foreign player if they sign Benatia, because they will have exceeded their allowed quota under Premier League rules.
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