The Colombian only joined move to Amsterdam from Atletico Nacional previous year but made a huge impression in his 46 outings last season, including a string of fine displays in Ajax's run to the Europa League final.
A new defender is on Pochettino's agenda and Sanchez emerged as a prime target late last week with widespread reports suggesting Tottenham were in talks for the Colombian worldwide.
Ajax have offered Sanchez an improved contract, but he has set his sights on a move to Tottenham, who are poised to open the bidding with a £28million offer.
However, De Telegraaf reported on Saturday morning that Ajax remain determined to retain the player, with director of football Marc Overmars telling the newspaper that the club have made Sanchez a "top offer" to sign a new contract.
Arsenal kicks-off English Premier League on a high
Danny Welbeck levelled matters in first-half stoppage time, completing a fast-paced, pulsating first half of action. That held until Arsenal took advantage of a lapse of discipline from Leicester right before halftime.
It is understood that the 21-year-old Tottenham target will now double his wages at Ajax to €60,000 a week - around £54,000 a week - which is comparable to what Spurs pay their defenders.
The Dutch club plan to keep him for one more year and expect to receive more than £60m for him next summer, with Barcelona among the clubs lurking.
Real Madrid and Barcelona were even dragged in by De Telegraaf, and whilst Ajax wanted their fans to know there was a tough stance against a transfer, it wasn't too hard to believe the pain threshold for a transfer had almost been reached.
Spurs are also reportedly chasing Celta Vigo youngster Pape Cheikh Diop, and are still looking for an additional forward.