Portsmouth boss Steve Cotterill will be without Liam Lawrence for the home clash with Sheffield United and has major doubts over the fitness of Hayden Mullins and Joel Ward.
Former Stoke midfielder Lawrence was named as a substitute for Tuesday night's 2-0 win against Scunthorpe but will now be out for a further two or three weeks after suffering a reaction to his calf problem during the warm-up.
Fellow midfielder Mullins limped out of the convincing win after just 22 minutes with a similar problem and is expected to be replaced with Aaron Mokoena, who scored the second goal against the Iron after stepping off the bench.
Ward missed the game altogether with a calf problem of his own and looks likely to miss out for the second time in a week.
Striker Danny Webber remains a long-term absentee as he continues his recovery from a cruciate injury.
Blades defender Shane Lowry has been handed an extra match ban by the Football Association and will miss out at Portsmouth.
Lowry, on loan from Aston Villa, was banned for last week's home defeat to Derby after his recent dismissal at Scunthorpe, but the Australian has been awarded an extra game on the sidelines for striking out at the dug out after he had left the pitch.
Manager Micky Adams could include midfielder Nick Montgomery (knee), on-loan West Brom defender Joe Mattock (ankle/knee) and striker Sam Vokes, who has been restricted to two appearances since arriving on loan from Wolves in mid-February due to a hamstring injury.
Club skipper Chris Morgan, fellow defenders Andy Taylor and Ryan France, goalkeeper Richard Wright, as well as striker Darius Henderson remain long-term absentees.
Adams is chasing his first win in 13 games since taking charge at Bramall Lane, while the Blades have not won any of their last 14 matches.