Frecklington, fully fit again following a calf injury, will now be handed a start in the engine room to complete his comeback after two appearances from the bench .
But Stephen Kelly will miss the game with a thigh issue, although his absence is mitigated by the availability once more of right-back Darnell Fisher, who is back from suspension.
Stubbs said: "It is fair to say Frecks will come back into the team at the weekend. His fitness has been good over the past ten days now.
"He came on after half-time at the weekend and you could see the impact that he gave the team even in a short space of time."
On Blackstock, who joined the Millers just after the transfer deadline and has been working on his fitness since, he added: "He is fit to potentially be in the squad. He has trained this week and we have looked to step it up a little bit and as long as there's no reaction today or tomorrow, then he will in the squad for the weekend.
"In terms of his experience, it would be a big boost in the arm for us as he obviously knows the division really well and his character will also bring out the best in the players. Not just that, he will set the standards among the group as well."
Defender Ahmen Belaid will be back at the club next week after two weeks back in France where he has been recuperating from a groin problem.