The St Helens born racer aggravated an old collarbone injury in last Thursday's 50-40 away win against the Panthers.
The Parrys International Wolves will now operate Rider Replacement in his absence with Luke Becker, Drew Kemp and Leon Flint eligible to cover his outings.
Club promoter Chris Van Straaten said: "It is a blow because Steve has really fired into form in his last few meetings for us.
"He actually top scored at Peterborough on Thursday evening and fully merited his place in Heat 15.
"But he's been in some discomfort over the weekend after aggravating an old injury and he's out of tonight's meeting.
"Forget about their current league position, Peterborough are a much stronger team than they have shown so far this year and they've got some real Monmore track specialists in their ranks.
"So tonight's task has just become even more difficult and as cliche as it may sound, we really are going to need the Wolverhampton faithful out in good numbers and fine voice this evening to be our extra man."
WOLVERHAMPTON: Sam Masters, Steve Worrall R/R, Luke Becker, Ryan Douglas, Nick Morris, Drew Kemp, Leon Flint.
PETERBOROUGH: Michael Palm Toft, Scott Nicholls, Hans Andersen, Ulrich Ostergaard, Chris Harris, Benjamin Basso, Jordan Jenkins.