Pompey will be without Joe Mattock for the clash with West Ham.
West Brom have decided to keep the left-back at the Hawthorns after being hit with a string of injuries.
Appleton had agreed tobring the 21-year-old in until the end of the season after Mattock impressed in seven Blues appearances.
But that has now been put on hold.Appleton said: ‘Joe’s on hold a bit because of the injury crisis West Brom have.
‘It’s hard because we would love to have him back here.
‘I speak to Joe and he would love to come back.
‘It’s difficult, but the door’s always open where he is concerned.’