Blackstock was forced off after 34 minutes of last Saturday's 3-1 home win over Wolves with a hamstring injury and he is a big doubt ahead of the game at the KC Stadium.
Fellow strikers Billy Sharp (chest infection) and Darius Henderson (knee) were also struggling last weekend and boss Billy Davies will hope that they have improved over the course of this week.
On-loan Norwich centre-half Daniel Ayala (hamstring) and fellow defender Dan Harding (calf) are both close to a return to the squad.
Davies remains unbeaten since returning as manager last month, stringing together five straight wins after drawing his first game in charge.
