Portsmouth midfielder Papa Bouba Diop has been ruled out for three months with a knee ligament injury.
The Senegal international picked up the problem with his posterior cruciate ligament in the 1-0 defeat at Arsenal on December 28.
"We'll be taking him back to see the consultant in six weeks and then we'll know a little bit more about it then," head physio Gary Sadler told the club's official website.
"He's in a brace and he's having treatment trying to get some of the swelling down on his knee."
Meanwhile, defender Glen Johnson is in line for a return from injury in time to face Manchester City on Saturday.
The England right-back has missed the last six games with a badly twisted ankle.
Fellow recent absentees Younes Kaboul and John Utaka have both also returned to training this week ahead of the visit of the Citizens.