Acquafresca is an option, with AZ Alkmaar’s Jozy Altidore and Manchester City’s John Guidetti among the Black Cats’ other targets.
The 25-year-old isn't as prolific as he was during his younger years at Cagliari, and Bologna could be interested in sending him to the Premier League for a season.
The Italian club spent £2million to sign him on a permanent basis last summer, following a loan spell at the club.
But he was then allowed out on loan to Spanish side Levante last season, where he netted just three goals.