It's not something that Real Madrid fans want to consider at the moment, but sooner or later there will come a time when the great Cristiano Ronaldo moves on and his contribution to the team is filled by others.

Quite how that happens is a delicate question of balance and quite possibly involving a sea-change of sorts in how the team is set up—but thankfully for Zinedine Zidane and Co., it's still likely a few years away.

Even so, it's such a question of importance that steps should already be taken to implement a long-term replacement, whether that be scouting potential replacements, grooming in-club starlets to fill the void or preparing to change formations entirely.

Perhaps the fans see that as happening already with the additions of young Spanish talent over the last couple of years. Perhaps they see a genuine world-class star elsewhere who will be ready to move to the Santiago Bernabeu to fill the No. 7 shirt when Ronaldo departs.

To gauge opinion and see who the best, or most likely, man to replace Ronaldo is, we spoke to four Real Madrid fans who gave interesting, and somewhat different, points of view on how to plug the gap that the Ballon d'Or winner will leave.

Wide or central?

Job No. 1: Which role is it exactly that Real will want to fill? Ronaldo has been an inside forward from the left for almost his entire Madrid career, but he has moved central more often over the last 12 months or so.

While there might not be another Ronaldo type who can power in 40 or 50 goals a season from the channel, Madrid fan and social outlet @UltraSuristic_ is in no doubt of what type of qualities are required in the eventual successor.

"For me it was Kylian Mbappe: in other words, a pacey winger.

"I don't know why Real Madrid fans, in particular, saw him as Karim Benzema's replacement when he isn't a striker.

"For now, though, Cristiano's successor goals-wise could very well be Marco Asensio. He's comfortable anywhere up front even though he thrives in a free role and prefers to play through the middle."

Perhaps given the way the greatest talent is congested around a few select sides in Europe right now, it's not surprising that our next fan in line, Sully, also goes for options from the Ligue 1 outfit.

"Successor implies either the marauding left-sided winger with goals or the adapted centre-forward with goals," he suggested. Either way, it's clear that the ability to find the back of the net regularly is a key part of the problem when it comes to identifying the right replacement for Ronaldo.

"His skill set simply can't be replicated, so the closest would be someone like Neymar or Mbappe in terms of their attributes and output—but it's not a likely occurrence before 2020 I'd think."

That might sound far into the future, but it's only a couple of seasons. After three years in Ligue 1, will Neymar fancy a return to one of Europe's biggest leagues? He'll be 28 at the end of the 2019/20 campaign, so still in his prime.

Mbappe will be just 21 years of age, but he could already have a World Cup and European Championship behind him, as well as four years in the Champions League.

No like-for-like

Goals and an ability to perform in the channel, then, but there is no simple swap to filling the Ronaldo-shaped hole that Real Madrid will be facing sooner or later.

Kiyan Sobhani, chief editor of fan site Managing Madrid, sees a bigger problem forthcoming: Everyone will be judged on a scale of one-to-Ronaldo, and thus found wanting.

"There is no such thing as a Cristiano Ronaldo successor," Sobhani said. "He is the mother of all statistical unicorns, and I have no idea when we’ll see a player close to him again.

"He defied the statistical norm and has skewed our perception of what greatness really is.

"Madrid are going to have to build a tactical plan which utilises multiple young, talented players and let the successor emerge organically.

"In a way, there's already a player who looks like he will have a great career at a very elite level in Asensio, and theoretically Gareth Bale would naturally take over, but the Welshman's health is an obvious issue.

"I'm not ruling out an eventual Mbappe signing either.

"He's young enough and has flirted with Real Madrid enough that his next move would be to join Real in his prime. The thought of him and Asensio together five years from now is exciting.

"But these questions are hard; Predicting the future is not easy no matter—where is Martin Odegaard, who is having a fantastic season and looks like he's meeting his projection just fine, going to be in a few years?

"He might step up, not in a Ronaldo role, but as an integral piece of the blueprint."

And therein might be the only way forward: If Ronaldo isn't around, and nobody can replace him directly, the game plan must revolve around the parts providing more together than they are worth individually.

Star target

There's a different option for Madrid to consider: After the best player leaves, simply replace him with the next-best.

He doesn't even have to be the same type, or the same style, but the next in line to be Madrid's star; the shape and the approach of the first team adapt to fit that new hero, essentially negating what Ronaldo did and how the team serviced him.

It would place a lot of stress on the new signing, but bringing in a genuine star, someone who can carry a team, is supposed to cover that mentality in any case.

Our final supporter, Malini, feels that might be the case—even if the best-seeming option out there right now is far from a guarantee to move to the Bernabeu.

"Neymar is the heir to Cristiano Ronaldo's legacy in Madrid. He has the skills, talent and ego to carry on what Ronaldo will leave behind.

"Naturally it can't be considered very realistic, especially after seeing what happened with Barcelona. The only aspects to bank on are that Madrid has a good relationship with Paris Saint-Germain and these rumours that Neymar Sr. is attempting to instigate his son's move to Madrid.

"Another PSG player, Goncalo Guedes, might be the alternative.

"He's currently shining at his loan spell in Valencia. He has an amazing shooting ability and incredible vision. It could be easier to take him off PSG's hands, as Neymar is their main man at left wing at the moment in any case."

It just might be that Paris is the destination to look at for Ronaldo's successor, one way or the other.

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