The success of today's double-header will go a long way towards strengthening the case for a Welsh side in Super League, although Saints will be more concerned with maintaining momentum at the top of the table.
Ironically, they are likely to need their third-choice scrum-half, John McAtee, who was on loan to the Second Division South Wales club earlier this season, although there is a chance that Bobbie Goulding could recover sufficiently from his cracked collar-bone to play.
Sheffield will not have Jon Sleightholme in their ranks. The England rugby union winger is only returning from a Barbarians tour today, but the possibility of him linking up with the Eagles for the summer is still alive and talks will take place next week.
The Eagles do have Keith Senior available after escaping suspension, but with both Ryan Sheridan and Dean Lawford injured, Matt Crowther is Mark Aston's partner at stand-off.
The South Wales side that plays Carlisle in the curtain-raiser includes two members of the victorious Welsh side in Carcassonne on Wednesday, Paul Moriarty and Gerald Cordle.
Wigan expect to have Va'aiga Tuigamala back from a hamstring injury for tomorrow's game against the London Broncos, although there will be late tests on Scott Quinnell and Kris Radlinski. London also have doubts about a number of players, including their props, Gavin Allen and Tony Mestrov.
Neither Saints nor Wigan can afford to lose ground against each other, but there is an equally important match at the bottom of Super League, where Workington could leap ahead of Leeds if they beat them at Derwent Park.
"You can't get away from the fact that this is a match between the two bottom teams and it is more important to us than playing Wigan last week," Dean Bell, the Leeds coach, said.
Tony Kemp will start his first game for Leeds since recovering from a broken arm, with Graham Holroyd moving to scrum-half and Dean Clark to loose-forward, with their new signing David Hulme also in the squad.
His brother, Paul, makes his debut for a Warrington side in which Mark Jones, impressive for Wales in midweek, replaces the injured Gary Chambers. Kelly Shelford, who has been talking to First Division leaders Salford, is left out after missing training.Reuse content