The timing could barely be worse. With the Clasico at Barcelona just around the corner, Gareth Bale is injured and the 27-year-old will be sidelined for up to three months after ankle surgery on Tuesday. It's terrible news for Real Madrid.
Bale missed Madrid's UEFA Super Cup clash against Sevilla in Trondheim back in August after returning late from his holidays because of his run to the semi-finals of Euro 2016 with Wales. But he has been virtually ever-present since then, featuring in 11 of his side's 12 games in La Liga and in all five in the Champions League - each of them as a starter.
With Cristiano Ronaldo still sidelined following the knee injury he picked up in the final of Euro 2016, Bale began the season with a bang at Anoeta, scoring two of his team's goals in the 3-0 win away to Real Sociedad. Since then, he has also netted versus Eibar, home and away to Legia Warsaw and a double in the 3-0 win over Leganes.
Against Atletico on Saturday night, he was used in a deeper role in midfield and set up Ronaldo's third in a memorable Madrid derby win for his team. That came after Zidane had picked a different formation to compete with Diego Simeone's side. With Bale until 2017 after limping off with an ankle injury in Lisbon on Tuesday, Zidane must shuffle the pack again ahead of the Clasico.
Real Madrid are at home to Sporting Gijon on Saturday, with a Copa del Rey clash against Cultural Leonesa to come on Wednesday night - also at the Santiago Bernabeu. And while the Blancos should be able to negotiate both of those fixtures comfortably, the trip to Barcelona represents another type of test altogether.