Spence, after enjoying as stellar season with Nottingham Forest on loan, has become one of the most in-demand right-backs on the market.
He has been linked with a number of clubs, but Spurs are heavily interested in him with Antonio Conte looking to him as his number one right-back target this summer.
Boro are willing to sell the right-back this summer but a lack of communication from Spurs has them entertaining notions of ulterior motives from the north London club.
Spurs enquired if the player was for sale at the beginning of summer but are yet to make further contact.
And the Championship club fear that it could be a tactic from Spurs to knock down the price set by them for the right-back star.
Speculation is rife that Spurs are set to lodge an initial bid of £10m for the right-back, but Boro are demanding an amount around double that.
Currently, the Championship club have no offers on the table for Spence and have taken a relaxed attitude towards the lack of commotion around him.
