The 28-year-old forward was considered to be a doubt for the Liga encounter after picking up an injury while on Champions League duty.
Bale impressed against Borussia Dortmund in midweek, scoring one goal and assisting another, but was forced off five minutes from the end after feeling the back of his leg.
Zidane conceded at his press conference ahead of the Espanyol clash that he could be without the Wales international, although hinted that he should be able to link up with his country this week.
He said: "It is a strain, so nothing too significant. But, as always, when a player has even a small problem then we don't want to risk it.
"As for him playing for his national team [next week], I don't think there will be any issue between Real Madrid and Wales.
"It will depend on his injury niggles and his state of fitness, nothing else. We will take it day-to-day.
"I'm not worried about the BBC, we will see them all soon."
Cristiano Ronaldo is the only member of Real’s famed ‘BBC’ frontline to be available against Espanyol.
Karim Benzema, like Bale, is nursing a knock, with a hamstring injury picked up in early September initially expected to keep him out of action for up to a month.
Zidane will, therefore, be forced to shuffle his pack, although he still has plenty of attacking options at his disposal.
The likes of Isco, Marco Asensio, Lucas Vazquez and Borja Mayoral are all available.
Real Madrid squad to face Espanyol:
Goalkeepers: Navas and Casilla.
Defenders: Vallejo, Ramos, Varane, Nacho, Achraf and Tejero.
Midfielders: Kroos, Modric, Casemiro, M. Llorente, Isco, Ceballos and Asensio.
Forwards: Ronaldo, Lucas Vazquez and Mayoral.
Defending champions Real sit sixth in the Liga table at present, with seven points having already been dropped during a frustrating start to the season.