Spanish federation rules at that time stated that players must serve a suspension in the competition in which the offence was committed, although since March 2015 bans picked up in the Super Cup have been served in subsequent La Liga games.
"A contract could be 10 years, or 20, but I know where I am and what I must do".
Madrid now takes aim at a second trophy to kick off the new campaign before starting its defense of the Spanish league crown the following weekend.
Just four months later he guided Real Madrid to the Champions League title after beating fierce rivals Atletico Madrid on penalties.
The champions have steadily strengthened their all-powerful squad as they bid to retain the Spanish league title for the first time since 2008.
"He is very good, he has had his holidays", said Zidane.
Modric, 31, must serve a suspension picked up for a sending off in Los Blancos' last appearance in the Super Cup three years ago.
Barca are still reeling from the loss of Neymar to Paris Saint-Germain for a world record 222 million euros ($262 million) with their attempts to land a replacement in Liverpool's Philippe Coutinho and Ousmane Dembele of Borussia Dortmund so far falling short. That match, however, was more about paying homage to the victims of the plane crash that decimated Chapecoense past year than warming up for Madrid.
Otherwise, the two sides would have to play out identical draws in this season's Clasicos, or win one each by identical scorelines - with Madrid having to have a better goal difference overall, for the Index's outcome to come true.
Ahead of Sunday's El Clasico, Zidane said: 'He (Ronaldo) has only been training with us for three days, but he's well and thinking about Sunday's game'.