The Daily Mail says despite enjoying two fruitful seasons with the Stamford Bridge club, Mata faces playing a bit-part role this season following the £30m arrival of Willian.
The Brazilian had already completed a medical at White Hart Lane but opted to join their London rivals, leaving relations between the clubs strained.
But that hasn't stopped Spurs considering a bid, although Chelsea have denied that an approach has been received.
Atletico Madrid were the first club to register their interest in the 25-year-old and are keen to take the Spain international on loan having lost Radamel Falcao, their talisman from last season, to Monaco over the summer for £50m..
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