John Halls who replaced him at Oakwell will step in for the injured Irish man. Lee Martin, Danny Webber, Chris Armstrong and Nick Montgomery will all miss out due to long term injuries.
Rob Hulse and James Beattie will fight it out to who starts up front with on form Billy Sharp. Hulse's performance against Norwich impressed Blackwell so he probably will carry on in the striking role.
Predicted line-up for Sheffield United:
1.Kenny
16.Kilgallon
5.Morgan
3.Naysmith
21.Halls
15.Speed
18.Tonge
16.Cotterill
14.Carney
9.Hulse
24.Sharp
There will be a live match thread of the game on Saturday starting from 2:00pm here on Blades Mad.