Portsmouth captain Sol Campbell is losing his fitness fight to face former club Tottenham at White Hart Lane on Saturday.
Hermann Hreidarsson, switching from left-back, deputised for Campbell in last Saturday's 2-0 win over Aston Villa but the veteran defender's hopes of a swift return from a knee injury appear to be slim.
A scan has revealed damage to the back of the knee, although the problem has now settled down and is responding to treatment.
But Pompey manager Harry Redknapp, already without key midfielders Sulley Muntari and Papa Bouba Diop who both start two-match suspensions, believes the visit to Spurs may be too soon for Campbell.
He admitted: "Sol is struggling. He looks doubtful for the weekend. We'll have to wait and see but I'm not too hopeful."
Redknapp will not gamble on Campbell's fitness with an FA Cup semi-final against West Brom coming up in just over two weeks.
He said: "When he did it (the knee) it didn't look like being that long but it has taken longer than I expected. Hermann did well though and he can carry on alongside Sylvain Distin."