Manchester United manager Louis van Gaal has refused to rule out making a bid for Roma midfielder Kevin Strootman.
Juventus are confident Arturo Vidal will not be lured away by Manchester United in the summer transfer window.
The 28-year-old has joined the club from Internacional for an undisclosed fee and has signed a two and a half year deal.
He becomes Gus Poyet's fourth acquisition this month following Spanish full-back Marcos Alonso's arrival on loan and the captures of Scocco's compatriots Oscar Ustari and Santiago Vergini.
Scocco was in the stands at the Stadium of Light as the Black Cats beat Stoke 1-0 to climb out of the Barclays Premier League relegation zone.