Dier, who can play either in midfield or central defence, is reportedly unhappy at his first team prospects under Mauricio Pochettino.
The Spurs boss seems to prefer a central midfield partnership of Victor Wanyama and Moussa Dembele, while it would be difficult to envisage Dier muscling his way past Toby Alderweireld or Jan Vertonghen at centre-back.
According to 'The Times', Chelsea are away of the Spurs player's situation and are ready to make a bid for the disgruntled England international, while Bayern Munich, who tried to sign Dier last summer, are also interested in the former Sporting Lisbon man.
In two-and-a-half years at White Hart Lane, Dier has played 106 games and scored four goals for Spurs.