King limped out of Saturday's 2-0 home win over Stevenage after sustaining a hip injury and faces a late fitness test.
Club captain John Mousinho featured as a substitute against former club Boro on Saturday, his first action since January's FA Cup reverse at the hands of Millwall due to persistent hamstring problems, and he is pushing for inclusion once more.
Keith Keane returns from a two-match suspension and will hope to dislodge on-loan Leeds defender Paul Connolly at right-back.
Fellow full-back Scott Laird broke his leg during the Deepdale clash against the Magpies and makes his latest visit to a specialist this week, although the 24-year-old's return to action will not come before next season.
Midfielder Joel Byrom is around a fortnight away from a return to full training following hernia surgery.