The Belgian centre-back has recently expressed concerns about his future with Spurs, as he seeks to secure Champions League football.
Following their weekend loss to Chelsea, Tim Sherwood openly questioned his side’s top four credentials, raising further doubts as to whether or not the Londoners are ready to return to Europe’s top table.
Vertonghen is already attracting attention from Barcelona, which may be a tempting option for him.
If Tottenham are unable to keep hold of their star, they will look to Valencia’s Mathieu.
Although not a direct alternative, the technically adept left-back would solve multiple issues in the Lilywhites’ backline.
The 30-year-old is able to play in the heart of the defence, but he is more comfortable on the left hand side.
His presence could allow the club to stick with an established central pairing and provide competition for Danny Rose – their only genuine left-back option.
Mathieu has a £17m release clause, yet it is thought that Spurs would look to pay a sum far below that.