Real Madrid midfielder Toni Kroos played down any notion of a rift between Cristiano Ronaldo and head coach Zinedine Zidane.

Ronaldo was substituted 18 minutes from time during Saturday's LaLiga match at Las Palmas, a decision he appeared unhappy with before Madrid subsided to a 2-2 draw.

Speaking ahead of Tuesday's keenly anticipated Champions League Group F meeting with Borussia Dortmund in his native Germany, Kroos insisted the three-time Ballon d'Or winner was in good spirits.

"The stories are bigger than what they really are," he told a pre-match news conference. "It's impossible for any player to play up to 60 games per season.

"The coach decides who must play and who must be substituted.

"Ronaldo trained with the team completely normally, as well as before the last game. He is ready for playing tomorrow."

A more pressing concern to Kroos might be the absence of Casemiro with a fractured leg.

Madrid have not tasted victory in the two full games since the Brazilian holding player sustained his injury in the 2-0 win at Espanyol earlier this month.

It has meant Kroos adopting a deeper position in Madrid's midfielder three but the Germany international is taking things in his stride.

"Casemiro is a fundamental part of this team, he protects us a lot - something we did not have before," he said. "But he is injured now.

"It doesn't matter much to me – playing five metres or 10 metres forward or back does not change my way of playing, which is to get on the ball."

Like his coach, Kroos does not think Madrid's results reflect a dip in form and he is relishing taking on Thomas Tuchel's free-scoring side.

"For us this is a good test," he added. "We can see where we are and what we can do this season. We're in good form."