Croatian great Prosinecki played for both Real Madrid and Barcelona during his career.
He told AS: "Arda Guler has great potential. I don't know if Carlo Ancelotti will give him more opportunities to have the minutes he would like. I can't say anything about Ancelotti's decisions but from my point of view Arda will improve every day, he will have many more minutes step by step.
"His football IQ is high... He is a very dominant player with the ball. He always thinks about attacking.
"A legend like (Luka) Modric? It is too early to answer the question of whether Guler will become a legend like Modric. Modric has been on big stages, he has been playing for Real Madrid for more than ten years. He is the captain of the Croatian national team, he has already played in a World Cup and Nations League final.
"Arda has a long way to go. To be like Modric he must constantly transform his potential into success on the pitch throughout his career."
Prosinecki added, "Real Madrid or Barcelona? I have much more important memories with Real Madrid. I have respect for Barcelona because it is one of the biggest teams in Europe. Frankly, Real Madrid is the biggest club in the world. I played there for three years. I left with a great memory and having seen what the club is like. For me, Real Madrid is always first."