Fax will be without Scott Murrell (hand) for the crucial clash, just four days after they scored 50 points against Whitehaven.
Harrison said: “We’ve got a massive encounter that everybody’s looking forward to. It’s a shame we’ve got Murrell injured, but that’s the way it is.
“Featherstone are very direct, very powerful and take their chances. We need to be at our very best.”
Featherstone beat Halifax 40-18 in the reverse fixture in April, but Sheridan insists that will not come into the reckoning for Thursday’s fixture.
Sheridan said: “We’ve beaten them at the Big Fellas, but it’s a different game at their place.
“It’s going to be a real war of attrition, but these are the games we like playing. We’ve a lot of confidence off the back of Sunday’s victory (against Batley).”