Spurs have been competing for Champions League qualification all season, a vast improvement from failing to earn continental football for the present campaign.
However, their charge has tailed off in recent weeks, Spurs suffering four defeats in succession before needing to come from behind to defeat Burnley at the weekend.
The North Londoners have conceded as many as 14 goals in their last five fixtures, leaving them with just the 10th-joint best defensive record in the Premier League.
As a result, reports have began to emerge regarding Postecoglou wanting to make wholesale changes, the Greek-Australian admitting himself that he is willing to significantly tinker with his squad.
Defenders placed on transfer list
Emerson Royal and Ben Davies - two versatile players who have not been first choice this season - are said to be available for transfer, while Japhet Tanganga will also not return to the fold.
According to Football Insider, there is the possibility that Postecoglou adds as many as four fresh faces to his squad in a bid to strengthen his backline.
Speaking on the outlet's Inside Track Podcast, senior correspondent Pete O'Rourke has suggested that Postecoglou is not overly convinced around the long-term availability of Cristian Romero and Micky van de Ven.
Romero has made as many as 31 starts in the Premier League, with three of the five games that he has missed down to a sending off against Chelsea in November.
Van de Ven sustained a hamstring injury in the same game and has been restricted to 25 starts, yet the pair remain as the automatic first-choice pairing when fit.
Radu Dragusin - who was brought in as a replacement for Eric Dier in January - has been limited to just 245 minutes in the top flight, making two starts and five substitute outings.
Cover at full-back wanted
As a result of Royal and Davies being made available, Postecoglou naturally wants two alternatives at full-back, as well as two more options for the centre.
Pedro Porro is the natural pick at right-back, as is Destiny Udogie on the opposite side, but Postecoglou is seemingly not convinced with his current backup.
Postecoglou has other options such as Ryan Sessegnon and Ashley Phillips that can be added to the senior ranks, yet Sessegnon has been plagued by injury and youngster Phillips has spent the second half of the season in the Championship with Plymouth Argyle.
A report has recently suggested that Spurs could raise funds for a rebuild by parting ways with as many as nine players.