Calla worked with Veiga last season as FC Basel assistant coach.
He told TuttoJuve.com: "He is a boy with a very strong character and an important personality that characterizes him. Renato likes to play the ball, to have an impact in a match and he always wants to win.
"What struck me right away is his physique, which is very important. He has excellent technique, but his presence on the pitch is truly incredible."
On Veiga's struggles at Chelsea, Calla continued: "I don't really agree with that, because he played a lot at the start of the season and the move from Basel to Chelsea is already very important in itself. In my opinion he is showing that he has good potential and the qualities needed to play at certain levels. Then it's clear that the competition in London is huge, he may have encountered some difficulties but that's quite normal.
"In my opinion he is a central defender, I would see him very well paired with (Fede) Gatti in the centre of Juve's four-man defence. On the wing I think there are alternatives who can cover the role better than Renato."
Asked about comparisons with Arsenal defender Riccardo Calafiori, Calla also said: "I don't really like making comparisons between two players with different characteristics. Ricky had a great year in Bologna and he can certainly be an important point from a motivational point of view.
"Renato can choose Juventus for the coat of arms, but also for Thiago Motta who was able to take the Felsinei to the Champions League and make talents like Calafiori explode. This can be a factor for the boy in the choice phase."