Reports linking the 33-year-old with a €100 million (A$158 million) switch to Turin have intensified with the move looking all but imminent.
The Portugal captain's impending departure leaves this World Cup shop window wide open for Los Blancos to exploit, and the demand from fans to improve on all fronts points to a big-money statement this transfer window.
Ronaldo, Fabio Cannavaro, Mesut Ozil, James Rodriguez; Real have rewarded the main stars from each of the last four World Cups with a move to the Santiago Bernabeu and Russia's installment could follow suit with another Galacticos-like response.
While it will be tough to replace a player like Ronaldo, there have been several stand-out performers who would have turned heads at the Spanish giants.
Odds-on favourite to win Best Young Player of the tournament, Kylian Mbappe will almost certainly remain at Paris Saint-Germain for the 2018-19 season.
The 19-year-old's permanent €183 million (A$288 million) move from Monaco officially came into effect on July 1, rendering him an indispensable asset for new manager Thomas Tuchel.
However, given PSG's expenditure over the past two seasons exceeding €425 million (A$670 million), UEFA's watchful eye could prompt the club to consider selling €222 million man Neymar in order to avoid punishment from Financial Fair Play.
Irrespective of his Oscar-worthy antics at the World Cup, the 26-year-old Brazilian remains the most obvious and marketable replacement for Ronaldo at Real Madrid, and while the club have denied their interest, another chance to infuriate rivals Barcelona could prove too good to pass up.
Neymar spent four trophy-laden seasons alongside Lionel Messi and co. between 2013 and 2017, scoring 105 goals in 186 games.
And while his eventual exit came down to a desire to step outside Messi's shadow, a lead role at Real may be the clincher in completing his Luis Figo-like switch.
But as far as World Cup performances go, Neymar's two goals and two assists in Russia pale in comparison to that of Golden Boot favourite, Harry Kane.
Having scored over 130 goals in his last four seasons with Tottenham Hotspur, Kane has already surpassed expectations with six goals in his maiden World Cup and will set a new England record with another against Croatia in Thursday's (AEST) semi-final.
Kane's productivity would be the ideal replacement for Ronaldo, who scored 44 goals in 44 games last season – more than picking up the slack for striker Karim Benzema, who had 12 in 47.
Be it Mbappe, Neymar, Kane or another standout star from football's showpiece event, Real Madrid need an answer – otherwise their three-year reign on the UEFA Champions League could be next to leave.
