Reigning World Player of the Year Cristiano Ronaldo hasn't ruled out a switch back to Manchester United. Reuters

Even though he was ruled out of Real Madrid’s friendly matchup against Manchester United Saturday in Ann Arbor, Michigan, superstar Cristiano Ronaldo still found a way to affect the match by hinting he would be open for another stay at Old Trafford.

Five years ago Los Blancos acquired Ronaldo from United for a then-record £80 million fee, but Ronaldo has said he still holds a “passion” and “love” for his old club, according to The Telegraph.

Speaking to reporters before the two teams clash in what could be the biggest crowd ever assembled for a soccer match in the United States, Ronaldo said he wouldn’t completely rule out a switch back to the Premier League.

“It was one of my favourite clubs, Manchester,” Ronaldo said. “Everyone knows that every time when I speak about Real Madrid I should speak about Manchester United, I loved it there.

“I was 18 years old (when I signed), I win everything there, the people treat me like a God there so I appreciate that and the future, nobody knows.

“I remember when we played there against Manchester in the Champions League, -- they kill me, my heart was so happy.

“I had fantastic moments and I appreciate this club. For me, it’s one of the best clubs in the world and I have passion for this club.”

Ronaldo also said that he maintains relationships with some of United’s current players, and that he built relationships with many people within the organization.

“I love Manchester, and to be back, I never know, you never know. Football you never know.

“Of course, I’m happy at Real Madrid, it’s my home, it’s my club, but Manchester treated me unbelievable so we never know.”

Before David Moyes took over as manager last season, the Red Devils were trying to bring Ronaldo back but he chose to stay with Madrid. United went on to post a highly disappointing season under Moyes, who was abruptly replaced by Louis van Gaal, while Ronaldo guided Los Blancos to a Champions League title.

Van Gaal is in the midst of turning United around, but spending £27 million on Luke Shaw and another £29 million on Ander Herrera pales in comparison to what he could spend on for Ronaldo.

With Ronaldo under contract through 2018, Madrid officials have given no inclination, at least publicly, that they are willing to part with the reigning World Player of the Year. United would have to equal or better Ronaldo’s perceived market value, which hovers just below £90 million.

However, Ronaldo is coming off a disappointing performance with Portugal during the World Cup. A serious knee injury limited his overall effectiveness and at one point doctors reportedly told him it could have been career-threatening.

Since joining Madrid, Ronaldo has scored 177 goals over 165 appearances, more than doubling his output from six years at Old Trafford.