The line-up was confirmed after the last day of the regular season yesterday, which saw Leigh relegated to Championship 1 and Dewsbury complete a perfect season in the third tier, with 18 wins from 18 games.
Halifax’s win over Toulouse on Saturday sealed a top-two finish, and they will enjoy a week off before travelling to Barrow in the qualifying semi-final.
Sheffield host Featherstone in the other preliminary semi-final, with the winner facing the winner of the Vikings clash with Whitehaven.
In Championship 1, Dewsbury earn automatic promotion as league champions, while Keighley and York go straight through to the qualifying semi-final having finished 2nd and 3rd respectively.
Oldham host Swinton and Hunslet travel to play-off debutants Blackpool in the preliminary semi-finals, with the winners of those two games facing each other for the right to play the loser of the qualifying semi.
Championship qualifying semi-final: Barrow v Halifax.
Preliminary semi-finals: Sheffield Eagles v Featherstone; Widnes v Whitehaven.
Championship 1 qualifying semi-final: Keighley v York.
Preliminary semi-finals: Oldham v Swinton; Blackpool v Hunslet.