“Any team would miss Cristiano and finding a replacement for him is almost impossible,” he admitted.
“When he left, the club intended for other players to cover his function – for the load to be spread among the other players in attack – and that’s not easy.
“Cristiano scored 50 goals [per season] and you can’t find a player out there who scores that many.
“Perhaps some of the other players had to take a step forward and not score 50, but 20. I’m not going to name names, but two or three players to score 20, 15 or 10 goals. We don’t have that and that’s our biggest problem this year.”
Real Madrid face off against Ajax at the Bernabeu on Tuesday night in the second leg of their last 16 tie.
The Spanish giants hold a slender 2-1 aggregate lead, but while they have fared relatively well in European competition, form in La Liga has noticeably declined this season.
Currently, Madrid sit 12 points behind rivals and league leaders Barcelona and five points adrift of cross-town rivals Atletico Madrid.
The club’s poor early-season form cost manager Julen Lopetegui his job, with Santiago Solari taking over.
But despite a solid start under the former reserve-team boss, Madrid have struggled to maintain consistency, as the club has found it tough to keep pace with their rivals at the top of the table.
Modric says that Ronaldo’s departure has been a major factor in that dip in form, but says the club and its current players cannot use it as an excuse.
“Cristiano is not here, but we can’t be complaining about that for 10 years,” he stated.
“The club has put its faith in other players like Bale, Karim [Benzema], Mariano, Vinicius [Junior,] who is doing really well.
“Sometimes things don’t work out as you want, but the way to solve that is by working. Madrid will always be at the top. Sometimes things don’t go well, but the team will be back.”
Meanwhile, Gareth Bale’s agent has slammed Real Madrid fans for their treatment of the Welsh star, branding them “a disgrace.”
The 29-year-old’s agent Jonathan Barnett said: “This generation of Real fans will be talking about Gareth’s goals for years to come.
“They should be ashamed of themselves. Those fans should be kissing his feet.
“Gareth deserves the greatest of respect. The way Real fans have treated him is nothing short of a disgrace.
“In the six years he has been in Spain, he has won everything. He’s one of the best players in the world.”
And Barnett addressed reports suggesting that Bale is seeking an exit from the Bernabeu club, saying his client is more than happy at the La Liga giants.
“Despite what the Spanish press are reporting, he’s happy, he speaks reasonable Spanish and there is no problem between him and the rest of the Real players. The people writing these things know nothing about him,” he said.
“There has not been one single discussion about Gareth leaving Madrid. He isn’t going anywhere this summer.
“Despite what’s been reported, he’s content, he wants to stay at Real and they want him.
“We’re fed up of fake stories that he’s leaving.”