Ipswich midfielder Colin Healy has been ruled out.
The Irishman could only manage 40 minutes of the midweek defeat at QPR before going off with a stomach injury.
Former Luton winger Adam Drury replaced Healy at Loftus Road and could be handed a starting berth in a 4-4-2 formation as boss Paul Jewell looks for a return to winning ways.
Captain David Norris is not expected back for another week or so as he recovers from injuries to his ankle and knee.
Goalkeeper Brian Murphy has stepped up his comeback from a broken ankle after coming out of plaster and will be back in around a month, meaning Marton Fulop will continue.
Kanu should return to the Portsmouth squad for the trip to Ipswich but Liam Lawrence remains a doubt.
Former Arsenal striker Kanu was absent from Tuesday night's 1-0 win over Crystal Palace after flying home to Nigeria for personal reasons but he is expected back in time for the weekend.
However, Lawrence is struggling to recover from the calf tear which kept him out in midweek.
The winger is using an oxygen chamber every day in a bid to speed up the healing process.
Boss Steve Cotterill will stick with a back four of Ritchie de Laet, Greg Halford, Ricardo Rocha and Hermann Hreidarsson after three successive clean sheets, meaning skipper Aaron Mokoena will have to make do with a place on the bench again.