The Ukraine international - who recently finished third in the Yashin Trophy ranking at the 2024 Ballon d'Or awards - has played second fiddle to Thibaut Courtois for the past six seasons in the Spanish capital.
However, Lunin was Carlo Ancelotti's main goalkeeper for most of the 2023-24 season due to Courtois's ACL injury, largely keeping Chelsea loanee Kepa Arrizabalaga out of the team before being dropped for the Champions League final.
Lunin has already played three times this season thanks to Courtois's renewed fitness woes, although two of those appearances ended in defeat, a 1-0 Champions League loss to Lille and the recent 4-0 El Clasico crushing at the hands of Barcelona.
Even though Courtois is still the undisputed number one when fully fit, Lunin was persuaded to sign a new deal with Los Blancos in the middle of September and is now tied down to the club until the summer of 2030.
Could Lunin be part of £67.4m 'swap' deal?
The Ukrainian's fresh terms will also allow Real Madrid to recoup a significant fee if he does decide to move on in the near future, and according to Defensa Central, that is likely to be the case if he cannot usurp Courtois.
The report claims that Portuguese giants Porto have identified Lunin as an ideal successor to their current number one Diogo Costa, who has long been linked with both Barcelona and Manchester United.
Porto have apparently devised a unique transfer plan for Costa and Lunin, who would be involved in two separate transactions totalling €80m (£67.4m), as the Primeira Liga side have slapped a €60m (£50.6m) valuation on Costa's head.
Porto would then use a good chunk of that money to sign Lunin from Real Madrid for €20m (£16.9m), and the 25-year-old would apparently be guaranteed the number one spot in Portugal.
Lunin joined Real Madrid from Ukrainian outfit Zorya Luhansk for €8.5m (£7.2m) in 2018, but he was loaned out to Leganes, Real Valladolid and Real Oviedo before making his first-team breakthrough.
The 25-year-old has now made 51 appearances for the Champions League winners in all tournaments, keeping 17 clean sheets, but he endured a nightmare Euro 2024 for Ukraine.
Lunin started his country's opening group game against Romania, but he let in three goals and was then dropped for subsequent clashes with Belgium and Slovakia as Ukraine suffered a group-stage exit.
Will Courtois or Lunin play against Liverpool?
Despite the El Clasico horror show, Lunin is guaranteed to hold his place in between the sticks against AC Milan in the Champions League next Tuesday and will likely start the following La Liga clash with Osasuna on November 9.
However, Courtois - who is currently out of the Belgium picture - is expected to make a full recovery from his groin issue during the international break, meaning that Lunin will likely drop to the bench for the UCL night with Liverpool on November 27.
Ancelotti's side were due to take on Valencia in this weekend's La Liga clash, but the tie has been postponed due to devastating flash floods in Spain.