Former Crystal Palace, Birmingham and Coventry striker Morrison, midfielder Sedgwick and defender Otsemobor have been released by the club, together with goalkeepers Richard O'Donnell and Sean Cuff, plus forward Vadaine Oliver.
Morrison has made 72 appearances for Wednesday since arriving on a free transfer from Coventry in the summer of 2010, scoring a total of 14 goals. The 33-year-old has had loan spells at MK Dons and Brentford this season.
Sedgwick, 32, who followed former Owls boss Alan Irvine to Hillsborough from Preston on a free transfer in June 2010, has made 58 appearances, scoring five goals.
Otsemobor, 29, also arrived at the club in 2010 after his release by Southampton. The former Liverpool trainee featured for the Owls on 37 occasions.
Meanwhile, Owls academy player of the year Jarrod Kyle will step up to first-year professional status and midfielder Mitch Husbands will stay with the club for another 12 months.