Amid that, Santos moved to clarify that the five-time Ballon d'Or winner was committed to playing for Portugal at the World Cup as they chase their maiden Jules Rimet Trophy.
"[Cristiano] has a big dream, that one I know," Santos said.
"He has this big dream of participating in what we are setting out to do, that is the goal of playing in a World Cup and winning it.
"That is the main goal, the rest has to stay away from the national team."
Ronaldo has played at four World Cups, with Portugal's best result during his time being in 2006 when they came fourth in Germany, while they were knocked out in the last 16 in both 2010 and 2018.
Portugal finished third at the 1966 World Cup before failing to qualify again for the tournament for another 20 years.
They won Euro 2016 with Ronaldo scoring three goals in the campaign, although he went off injured early in the final.
Portugal will return to competitive action later this month with World Cup qualifiers against Azerbaijan, Serbia and Luxembourg.