Genoa sign Miguel Veloso
The deal involves Genoa's Alberto Zapater moving to the Portuguese side.
Veloso, a left-footed midfielder who was a product of Sporting's academy, played 51 times for the club.
He earned the first of 14 caps for Portugal in 2007 and was in the squad for the World Cup finals in South Africa, but made only two appearances as a late substitute in the group stage.
Spanish defensive midfielder Zapater, 25, moved to Genoa last year after spending five seasons at Real Zaragoza.