Defender Winston Reid has signed a new long-term contract with West Ham which commits him until the summer of 2021.
Blackburn have signed defender Doneil Henry on a month's loan from West Ham.
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.