Ronaldo left Real for Juventus last summer in a deal worth €112m.
Suarez said, "The transfer of Cristiano Ronaldo? Obviously, this was a small surprise because of the quality of his performance in Madrid.
"But also for everything he had won there and the way Madrid helped him grow up. So it surprises you a bit, but it's football.
"One day you can say that you are happy where you are, and the next day things can change. It's a decision that must be respected."