Ex-Real Madrid coach Fabio Capello says the main reason for the team's current issues is that Cristiano Ronaldo is "not perfect physically."

Madrid began the 2016-17 season with six straight wins in all competitions, but have since drawn four games in a row for the first time in over a decade, leading coach Zinedine Zidane to have to deny that the team is now in crisis.

Ronaldo, 31, began his preseason late after recovering from a knee injury picked up in the Euro 2016 final, but has played in all four of the drawn games, scoring once.

Speaking on Onda Cero radio show El Transistor, veteran coach Capello said that when Madrid's "best player" was not at his physical best then the team as a whole suffered.

"Real Madrid's current problem is Cristiano Ronaldo," the Italian said. "Because for me he is not perfect physically, he does not have the same balance with his knee. I have seen him missing shots that he never misses, never. And he is their goal scorer and the most important player in the team. Then they are missing important midfielders too."

Capello said that those questioning Zidane's coaching ability after below par recent performances should remember the rookie coach guided the team to the Champions League trophy just a few months back.

"When you win trophies, well, and Zidane has won the Champions League, the most difficult to win for everyone," he said. "So we must give him time. This is a difficult moment, and they are still top. That is the most important for a coach."

Madrid's slip in form has also coincided with injuries to key players Luka Modric, Casemiro and Marcelo, with Fabio Coentrao yet to play this season. James Rodriguez, Karim Benzema and Raphael Varane all then picked up injuries in Sunday's 1-1 La Liga draw at home to Eibar.

This week has brought better news for the club with Marcelo and Benzema having returned to training, with the Brazil left-back and France centre-forward now likely to be fine for the game at Real Betis after the current international break.

"In what was the first training session of the week at Real Madrid City, Zinedine Zidane's charges trained alongside the Castilla squad in a session which was marked by the absence of the 15 madridistas who have been called up by their national teams," a club statement said.

"Kiko Casilla, Ruben Yanez, Marcelo, Danilo, Karim Benzema and Mariano trained on Pitch 3 with players from the club's B-team in a session which saw the ball take centre stage. Fabio Coentrao trained indoors, whilst Casemiro and Luka Modric continue with their recovery processes."

Casemiro's likely return date remains unknown, but the Brazil international told Real Madrid TV that he was hurting being outside unable to help during their current poor results.

"I'm working hard to get back as soon as possible," Casemiro said. "It hurts more when I am not on the pitch as I cannot help out. I am left very angry as I want to be out there sacrificing myself for my teammates. It is hard to be outside and not able to help."

Holding midfielder Casemiro played 13 of Madrid's record run of 16 consecutive La Liga wins, with their sequence of draws beginning in the first game he missed through injury, and he said he knew he was an "important player" for the team.

"I know that my teammates want me back at my best," Casemiro said. "I must relax and return even stronger. My analysis is that I am an important player, like everyone. We must give credit to everyone."

Casemiro stressed that Zidane's side are unbeaten this season, still joint top in both La Liga and their Champions League group, and had lifted the European trophy just a few months ago.

"The sensations are the best possible," he said. "We are joint leaders, doing well in the Champions League. You must not forget that this squad won the Champions League, it is a strong squad and we are not going to fail."