The German international arrived last January in a cut-price move, but has struggled for playing time since making the switch to White Hart Lane.
With new manager Tim Sherwood’s change in playing style, Holtby looks set to spend even more times on the peripheries of the starting XI, leading to talk that he will be allowed to leave before the transfer deadline passes.
Spurs are thought to be prepared to listen to offers for the 23-year-old, with the midfielder’s former club Schalke one side with a keen interest.
Holtby earns an estimated £67,000-per-week, which Tottenham are keen to get off of their expenditure as they look to free up space and funds for arrivals in the coming weeks.
They are unlikely to make much of, if any, profit on the player – who cost just £1.5m last year.
The North Londoners are also considering allowing Etienne Capoue to leave.
The Frenchman only joined the club over the summer, but is already attracting interest from Napoli.