Forlan was a teammate of Valverde's at Penarol in the 2015/16 campaign.
"He has the qualities to keep growing," Forlan told Radio MARCA when asked about Valverde.
"He's a good boy, a good professional.
"I'm not at all surprised by what I'm seeing of him, because [his qualities] were already there.
"He is gaining confidence, maturity, experience and is a player that Real Madrid's supporters will enjoy for many years.
"I'll risk saying that he can become in midfield what Sergio Ramos has been as a defender.
"I'm not surprised by his emergence, because it comes with age.
"Nowadays he's realising where he is and he's [now got] the maturity of life.
"That will help him a lot; the confidence, maturity, knowing the conditions he has and that he is appreciated a lot at the club."