The 25-year-old spent the second half of last season on loan at Easter Road and was part of Pat Fenlon's starting line-up for the William Hill Scottish Cup final defeat by Hearts.
Soares joined Stoke from Crystal Palace for £1.25m, before a temporary move to Hibs sounded the end of his time at the Barclays Premier League club. He joins nine other players in leaving the Brittania Stadium.
Meanwhile, Ian Murray has been linked with a possible move to DC United in the United States following his release from Hibs. The American club are monitoring the defender's situation after he was released by Fenlon at the end of his testimonial season with the Easter Road side.