The initial agreement did not include a fixed fee for a permanent transfer, but former manager Ange Postecoglou had expressed his desire for Tel to stay with the team in the long term.
Although Postecoglou has since been replaced by Thomas Frank, the club is still moving forward with plans to acquire Tel, according to recent reports.
Tottenham is said to be in close negotiations with Bayern Munich to secure a permanent transfer for the 22-year-old player.
The club is expected to pay a transfer fee of €35 million for Tel.
