​In what world does it make sense for Manchester City to sanction the sale of Leroy Sane?

He's 23 years-of-age, showing glimpses of his immense talent on an increasingly regular basis and can change games in an instant. Allowing the quicksilver winger to leave is illogical for a myriad of reasons.

Leroy Sane

The ​asking price for Sane is believed to be north of £80m, which is quite obviously an enormous sum of money. Is it enough? No. It's nowhere near what he is worth to the ​Citizens.

In his three seasons in the ​Premier League following a £42m switch from Schalke, supporters have watched raw, untamed potential slowly mature, and producing devastating displays out wide. Imagine what kind of skill-set the youngster could possess in another three years.

That thought alone should convince City that they need Sane at the club. This is man built for elite-level football; frightening pace, hunger, superb technical ability... he has all the tools to reach the top of the game.

Were they to miss out on what the German international can offer in the future and instead have to watch him tearing things up with ​Bayern Munich, Pep Guardiola and his team would surely look at their £40m profit and wonder how on earth they ever believed it was a good deal.

This scenario is comparable to a high-profile transfer that took place a decade ago, namely Cristiano Ronaldo's £80m move to ​Real MadridNo, Sane is not on the same level as the Portuguese, though there are no doubt similarities. 

The key takeaway is that ​Manchester United were the big losers in this one, despite making a staggering amount from his sale. 

Ronaldo single-handedly ended a woeful period in Los Blancos' history and restored them to their European throne, while United endured a steady decline in the years following his exit. Their neighbours would do well to remember that a huge fee doesn't guarantee a worthwhile deal in the long-term.

With regard to the present moment, keeping him at the Etihad Stadium maintains the remarkable squad depth that was necessary for Guardiola to deliver the treble. You can't mount a challenge across multiple fronts unless you can rest players and avoid a significant drop-off in quality.

Vincent Kompany,David Silva,Leyroy Sane,Ederson,Kyle Walker

If the City hierarchy have hopes of lifting the ​Champions League next season - which they clearly do - then they have no choice but to keep the likes of Sane in the north-west.

More to the point, however, the starlet should be playing in the big games, not just helping the side navigate the early rounds of the League and FA Cups. He's a match winner, capable of unpicking any lock.

Recall Sane's game-clinching goal against ​Liverpool in January, a goal which proved pivotal in the title race. The opportunity was hardly straightforward; most wouldn't have given Alisson anything to really think about.

Having him available allowed his manager to change approach and present the Reds with a unique threat, which cannot be stopped when in full-flight.

This is a weapon which Guardiola cannot afford to let go. The wideman offers a fabulous combination of physical prowess and masterful skill, the likes of which is otherwise unseen in the squad. Put simply, he cannot be replaced.

It seems that his coach is often averse to selecting Sane in the big fixtures because of an apparent attitude problem. With time and experience, that will cease to be an issue and the player will reach a new level, on which he is wholly in control of his emotions and able to focus on the task at hand.

Look at what happened when teammate Raheem Sterling grew up? He's only a year the German's senior, but there is a marked difference in maturity. Once the England forward began to take on more responsibility, he started showing far better form and achieved a greater consistency.

It is not unreasonable to think that Sane, too, could become a reliable performer when he attains a certain age, and he may not be far from it.

Leroy Sane,Raheem Sterling

It should be clear by now that Sane is too young and too talented to be sold. Letting him go now means that the Citizens see none of his best years. They risk losing him when he is on the cusp of something special. They will rue allowing him to leave for Bayern.