John McGreal's knee injury picked up during last night's reserve game against West Ham has been revealed as medial ligament damage - the same problem he suffered during the Brighton game before Christmas.
The defender was stretcherd off in the 34th minute of last night's game after a challenge by West Ham's Daryl McMahon.
The swelling on his knee is so severe that he will be unable to have an x-ray until next week.
Boss Joe Royle, who watched Portsmouth beat Burnley and claim prootion last night, was disappointed to hear the news: "I feel terrible for John, he is a thoroughly nice man who doesn't deserve this.
"And it has hurt us not having him. He was in outstanding form until he got the original injury at Brighton and since then we have not had many clean sheets. We would certainly be points better off if we had had him fit all season."
More bad news for Royle was Reading's 5-1 thrashing of Preston which all but confirmed the Royals in the play-offs.