Michael Appleton has challenged his Pompey squad to cope with the Derby absence of Chris Maguire.
The on-loan Rams striker is unable to play when his parent club visit Fratton Park on Saturday.
It leaves a gaping hole in the Blues’ attacking capabilities for another must-win encounter in their bid to remain in the Championship.
Maguire has been a revelation since his joining on an emergency loan in March, scoring three goals in 10 matches.
Ashley Harris, Marko Futacs and Luca Scapuzzi are possible replacements, while Kelvin Etuhu may return following a family bereavement.
In addition, Dave Kitson could partner Luke Varney in a front two.
Regardless, Appleton is looking for one of his fringe players to successfully step into the breach.
He said: ‘Not having Chris against Derby is going to be a big, big disappointment for us because I thought he was outstanding against Palace.
‘In the first half he was superb, getting the ball in wide areas and cutting in.
‘It is going to be a big loss but an opportunity for one of the other players.
‘I thought young Ash (Harris) came on and looked as though he had been in there for the last two to three years really.
‘He was calm, collected, showed a cool head, got on the ball and wanted the ball.
‘Kits has also responded well from the chats we have had over the last few weeks and put a right shift in against Palace.
‘As for Kelvin, he had a family bereavement over the weekend and I’ve given him a few days to be with his family.
‘I will be in contact with him over the next 24-48 hours and if his mind is in the right place and he is ready to be involved on Saturday then he will be involved. But family comes first.’