Hughes is without Ryan Nelsen (hamstring) and Brett Emerton (calf), while midfielder Tugay starts a three-match ban following his dismissal in the final game of last season.
Steven Reid, meanwhile, is doubtful with an ankle injury sustained on international duty with the Republic of Ireland in midweek.
Portsmouth are set to hand competitive debuts to four of their summer signings.
Defenders Sol Campbell and Glen Johnson, goalkeeper David James and striker Kanu are all set to start, with fellow new recruit midfielder David Thompson on the bench where untried 17-year-old Nick Jordan is the only available cover for James.
Frontman Lomana LuaLua is out on a long-term basis with an ankle ligament damage sustained in a pre-season friendly, record signing Benjani Mwaruwari is a doubt with a thigh injury, while goalkeepers Dean Kiely (thigh) and Jamie Ashdown (broken thumb) are also missing.
Teams:
Portsmouth (from): James, Johnson, Primus, Campbell, Pamarot, Stefanovic, O'Neil, Mendes, Davis, Taylor, Todorov, Kanu, Benjani, Thompson, O'Brien, Hughes, Songo'o, Griffin, Jordan.
Blackburn (from): Friedel, Neill, Khizanishvili, Savage, McCarthy, Reid, Bentley, Pedersen, Mokoena, Jeffers, Gallagher, Roberts, Douglas, McEveley, Gray, Kuqi, Peter, Enckelman.
On level ball, I'll be with Portsmouth. I expect them not to lose today on their home soil.