Viviano says Vlahovic has gone backwards since his time with Fiorentina.
He told TV Play: "In fact the other day was embarrassing, he seems to have regressed from all points of view.
"Today he doesn't play sparkling football, but different and he is one of the main responsible for the fact that Juventus doesn't play well."
On Juventus struggling to get shots on goal under coach Thiago Motta, Viviano says: "If we reduce everything to that... I didn't like (Massimiliano) Allegri's and I'm not liking today's. Last year there was a match in which there were 0 total shots. In the end Thiago Motta hasn't lost yet, he won well in the Champions League, he has one more point than Milan and Inter... He could have done better with Napoli, he's missing the victory with Empoli, he would have been first in the standings.
"Not good, but it shouldn't be considered a disaster either, otherwise the trials will start. You gave Allegri 3 years for an Italian Cup, 5 league games are not enough for Thiago Motta, right?"