"We will see tomorrow [how he is]", Zidane said when asked about Bale's availability during Saturday's pre-match press conference.
Chris Coleman's side travel to Georgia on October 6 before hosting Ireland in Cardiff three days later.
Zidane said of that: "Regarding the national team, I don't think there will be a problem between Madrid and Wales. It depends on his state of fitness, we will see day-by-day".
It seemed nearly inevitable that the political discourse of the day would also find its way into Sunday's clash, with BBC News reporting 761 people were injured by police attempting to stop the voting in the Catalan referendum.
They will be looking for their first league win at the Santiago Bernabeu against Espanyol, who have proved accommodating opponents in recent years, losing their last 10 games against Real in all competitions.
"We can change all of [the talk about poor home form]".
It's unclear why there is such a difference in results at home and away this season, but the demands of the fans in the Bernabeu, where nothing else than a win will suffice, could be one reason and supporters have been quick to latch onto errors and boo players such as Gareth Bale and Karim Benzema.
Zinedine Zidane's side have picked up just 11 points from a possible 18 in La Liga so far. "The most important thing for him is to play and be on the pitch against Espanyol", he concluded. "It is a good stadium to try to demonstrate that we are competitive".
And, this comes with Marcelo and Theo Hernandez also out. "It is a club issue, a discussion between the club and Cristiano", the former French International said.
Barca had earlier extended their flawless start in La Liga to seven games in extraordinary circumstances as they beat Las Palmas 3-0 behind closed doors at the 99,000 capacity Camp Nou following the police crackdown over an independence vote deemed illegal by the Spanish government.