When the North Londoners signed the defender from Real Madrid in 2020, they shelled out a fee of £27.5m for a player who they had hoped would become a mainstay in the team.
For two seasons, the Spain international generally made a positive impression, making 53 starts and nine substitute outings in all competitions.
However, Reguilon fell down the pecking order under Antonio Conte and has subsequently spent loan spells at three different clubs since August 2022.
After failed stints at each of Atletico Madrid and Manchester United, the 27-year-old was able to kick-start his career with Brentford during the second half of 2023-24.
Four assists came from 14 starts and two substitute outings in the Premier League, yet it appears that it was not enough to tempt Ange Postecoglou into retaining his services.
Spurs settle on asking price for Reguilon
With just a year left on his contract, there is an urgency for Spurs to cash in on the left-back, aware that he will not be short of admirers.
According to Football Insider, Spurs chairman Daniel Levy is prepared to accept offers in the region of £10m.
There have already been significant incomings and outcomings in the summer transfer window with Spurs paying in excess of £40m to sign Archie Gray and Lucas Bergvall on permanent deals and Timo Werner on loan.
Although several high-profile releases have materialised, the only substantial fee generated is the £10m from the sale of Joe Rodon to Leeds United.
Spurs also seem likely to cash in on Emerson Royal, who is attracting interest from AC Milan, and that would leave Destiny Udogie and Ben Davies as Postecoglou's left-sided options for the time being.
Ten Hag to reunite with Reguilon?
When Reguilon was at United for the first half of last season, he made 12 appearances in all competitions, accumulating 655 minutes during that period.
With Luke Shaw and Diogo Dalot as competition, it was a respectable return, but it remains to be seen what Reguilon made of Ten Hag and United activating a break clause in the agreement with Spurs.
United do need reinforcements given Shaw's injury issues, and signing Reguilon for a cut-price fee theoretically makes sense.
That said, Reguilon has got a taste of regular football at Brentford, potentially leaving him to cast his net wider and prioritise game time over the size of an interested club.