With both Toby Alderweireld and Jan Vertonghen well into the final year of their respective contracts, it's a concerning time for Tottenham Hotspur as the beginning of a new era looms on the horizon. 

Tottenham's formidable defensive partnership consisting of Belgian compatriots Alderweireld and Verthonghen has formed the backbone of Mauricio Pochettino's success since joining the club, but the end of an enticing chapter in the club's history is edging ever closer.

Murmurs coming from north London have hinted that Vertonghen is prepared to sign a contract extension, but those murmurs have not been echoed in the context of Alderweireld's future.

Whether either of the aforementioned pairing agree to new contracts before July 2019 remains to be seen, however, considering both players will be the wrong side of 30 next summer, Pochettino will naturally be exploring his options in the transfer market in the coming months.

Well, according to a recent report from Sky Sports, that process is already well underway.

The report claims that Tottenham are closely monitoring Nathan Ake's progress, with the need to sign home-grown players a notable factor contributing to their interest.

But Tottenham's dream of signing Ake should be placed on hold for the time being, as the same report claims that Chelsea have a 'gentlemen's agreement' in place which would allow them to re-sign the Holland international for £40 million.

Considering the quality and consistency of Ake's form since signing for the Cherries it's fair to say that Pochettino's interest is thoroughly justified.

Ake is one of the best central defenders in the Premier League and at 23-years-old he has the potential to blossom into a mainstay at the heart of Tottenham's defence.

Combining his natural ball-playing ability with first-rate anticipation and composure, Ake possesses a set of attributes which are perfectly aligned with what Pochettino demands from his defensive players, so there's no doubt his acquisition would be a stroke of genius by the club.

But with David Luiz's contract also set to expire in 2019 and Chelsea's general lack of strength in depth in central defence to take into consideration, it would be no surprise if they exercised their agreement with Bournemouth next summer.

Naturally, Tottenham could yet convince Ake that his future would best be served in north London regardless of Chelsea's interest, but the agreement in place certainly proves that Pochettino should be prepared to face a battle in his bid to secure Bournemouth's crown jewel.

Tottenham fans - thoughts? Let us know below!