Cristiano Ronaldo quit Real Madrid for Juventus back in July, swapping Spain for Italy in a huge £105million transfer deal.
Since then, both his former and current sides have experienced differing fortunes. While Juventus are on course to win the Serie A title again, Real Madrid face a huge fight to dethrone Barcelona as La Liga champions.
Ronaldo scored 450 goals from 438 games for Real Madrid prior to his Juventus move and, after the club failed to sign a replacement, many expected Los Blancos to toil.
Julen Lopetegui has already made way for Santiago Solari as manager, losing his job in October.
And Capello believes Real mistakenly thought they could cope without Ronaldo after the player jumped ship.
“Maybe Real Madrid will be going into this worse in terms of form,” he told La Gazzetta dello Sport.
“They are paying the price for thinking that it would be easier to win without Cristiano Ronaldo, and that the results would be the same.
“When Cristiano was at Real Madrid, their rivals were frightened, and his team mates felt more liberty.
“He can create problems at any moment. But having said that, Madrid still have a lot of quality. And Marcelo and Carvajal are now back from injury.”
Real’s attack has faltered since Ronaldo’s departure.
Gareth Bale, Marco Asensio and Karim Benzema have all failed to step up in the absence of the Portugal international.
But Capello thinks Solari has as many problems at the back as he does going forward.
“The directors don’t make these decision based on charm, although there has to be a group of players who listen to the president,” he added.
“I’m not too worried about the most recent defeat, but more about what they’re doing well and doing badly.
“We know they’re not defending well in their area, but they do have Courtois who gives them security.”
Ronaldo is primed to start when Juventus face Valencia in the Champions League tonight (8pm).
Real Madrid are in action at the same time, tackling Roma at the Stadio Olimpico.