The season ended less than a month ago, and so much has already changed at Tottenham Hotspur.

In the space of a week, Ange Postecoglou, who led the club to their first trophy in almost two decades this season, was fired, and his replacement all but announced.

The man to come in and try to improve the Lilywhites' Premier League form looks set to be Brentford's Thomas Frank.

However, to ensure the Danish coach can do that, Daniel Levy and Co have to execute this summer perfectly, which means bringing in the right players and selling those who need to be sold, such as Son Heung-min and another big name.

Why Son should be sold

There is no doubt that in the pantheon of great and iconic Tottenham Hotspur players, Son is right near the very top, as not only has he spent a decade at the club, but he was the captain for their Europa League triumph last week.

However, that is one of the reasons he should be moved on this summer, as if he were to go now, he'd be leaving on an incredible high and as an unquestionable legend of the club, but were he to remain for another year, there is every chance his declining ability would see him eventually leave on something of a sour note next year.

It's not the South Korean superstar's fault he's become less effective in recent years, but just an unfortunate reality of getting older, a reality supported by research carried out by The Athletic showing that wide attackers peak at 26 and see their ability to take defenders on nosedive at 30 and beyond.

We can also see this in his numbers, with the Chuncheon-born ace racking up 27 goal involvements in 36 appearances last year but just 23 in 46 games this year.

Moreover, per FBref, the 32-year-old sat in the top 9% of attacking midfielders and wingers for successful take-ons per 90 in the 18/19 Premier League season, but then this season, he was in the bottom 42% for the same metric.

Now, the good news is that the North Londoners can probably still get some good money for the Bayer Leverkusen star, as according to French outlet Foot Mercato, he has been approached by Saudi Pro-league side Al-Hilal, and as we've seen in the past few years, they can pay an awful lot for ageing stars.

In all, Son is now a bonafide legend at Spurs, but this summer feels like the right time for him to go so he can leave on a high, and the club can cash in, which is the same for another star.

The Spurs star who should be sold

While there are a few players who should be sold this summer because they simply aren't good enough, like Yves Bissouma, we are talking about one of the co-vice captains, Cristian Romero.

Now, before the pitchforks and torches come out, we are not for one second saying the Argentine isn't good enough to play for Spurs under Frank.

However, there are a few reasons why the North Londoners should probably be looking to cash in on him, with the first being the interest.

There has always been the odd link here and there for the World Cup winner, but it has to be said that in the last few months, said links have increased in volume and believability.

For example, Real Madrid were reportedly keen on the former Juventus ace in early April, but since then, there has been a near-constant stream of reports touting him for a move to their city rivals, Atlético Madrid.

Worse still, the Córdoba-born "monster," dubbed by journalist Charlie Eccleshare, has reportedly already spoken to his compatriot Diego Simeone and now wants to move to the Spanish capital, which is a want likely strengthened by the sacking of Postecoglou.

The second reason is intertwined with the first and concerns the money involved in a potential move.

If the club can get upwards of £60m for the wantaway defender, as it looks like they want, then that cash can go towards new players that actually want to play for the team and that Frank personally wants in his squad.

Finally, the the £165,000-per-week defender cannot be relied upon to remain fit anymore, as he missed a whopping 27 games for club and country this season, so even if he stays this summer, he could well end up missing half of the 25/26 campaign.

Ultimately, Romero is a brilliant footballer and was important in the Europa League this year, but with him increasingly looking like he wants to leave, combined with his fitness problems, it would make sense for Spurs to cash in now and hand Franks the funds to sign his own players.