The Brazilian forward has nothing but praise for the defender and Mario Gotze, and is optimistic about the Blaugrana's chances in the Champions League
The Blaugrana are keen to add fresh blood to their defence in the summer transfer window and the Germany international is reportedly one of their top targets - much to the delight of the Brazil veteran.
"Hummels is physically very strong, has good technique, accurate passing and wins the majority of his challenges," Ronaldinho was quoted as saying by Sport Bild.
"He has a lot of qualities that not many defenders have. I am confident that he has what it takes to play for Barcelona."
The Atletico Mineiro star then went on to praise BVB youngster Mario Gotze and believes the attacking midfielder can become a superstar in his own right.
"I don't know all the Borussia Dortmund players, but I do know the small technical guy in midfield, Gotze. He has incredible skills," he continued.
"The way he handles the ball and plays passes is simply amazing. He has all the abilities to become a world-class player."
Ronaldinho, who won the Champions League with Barca in 2006, also had his say on the upcoming semi-final clash between Tito Vilanova's side and Bayern Munich.
"Barcelona are the top favourites for me. I hope they can win the Champions League. They showed up when it mattered most earlier this campaign against AC Milan and Paris Saint-Germain.
"That shows they are an excellent team that can cope with the pressure. That's very important at this stage of the competition."