A new right-back stands as a priority after midfielder Jason Lowe took up the position in the injury absence of Adam Henley and Bradley Orr against Millwall on Wednesday night.
On-loan QPR striker DJ Campbell, who was cup-tied for the FA Cup sixth-round replay defeat, is laid low with an ankle problem and joins an extensive casualty list that includes David Bentley, Colin Kazim-Richards, Dickson Etuhu and Lee Williamson.
"We've got Adam Henley and Bradley Orr, who are both going to be out for a while, so Jason Lowe's had to play at full-back and we'll probably look in that area," said Appleton, who also saw Markus Olsson and Josh King sustain hamstring problems against the Lions.
"DJ's picked up an ankle injury as well, so we have to assess that one.
"David Bentley missed the (Millwall) game because of a medial knee ligament injury so there's plenty of work and plenty of things for us to do in the next 48 hours."