The Wales worldwide fell out of favour with Zidane during the Frenchman's final season in charge, and his return may force Bale to consider his future should he get the impression that he'll once again be on the peripheries of the starting XI.
"What I think is that this team needs to continue winning but I think it needs a change, a different voice, another methodology", he said at a news conference explaining his resignation previous year.
Zidane replaces Santi Solari with immediate effect and will be in charge for the remaining 11 games in the season.
Zidane, who led Real to three straight Champions League titles, one of them a part of a historic Liga-Champions double, will assume first-team coaching duties as early as tomorrow morning.
Zinedine Zidane is back in charge at Real Madrid less than 10 months after stepping down as their boss.
It is said the former France star will be confirmed as a replacement for Santiago Solari on Monday at around 1800 local time (1700 GMT).
A major difference between the Real Zidane left and that which he is re-entering is Cristiano Ronaldo no longer being at the club.
"I understand Mourinho will sign a deal for the remainder of this season and for another three years, with a net salary of £17m per year", he wrote in the i newspaper.