Several of the game's leading players - including Castleford's Frano Botica (with Orrell) and Widnes' John Devereux (Sale) - are to become all-year-round footballers following league's switch to a summer season and union's decision to go professional.
However, Murphy, Warrington's football executive, has ruled out any of his squad pursuing a career in both codes. "No player will be allowed to play rugby union. It's club policy," he insisted. "John and I have discussed it. There's far too much happening in rugby league for us to let them go.
"The only way Warrington players will be allowed to play rugby union is if they go to union full-time."
Dorahy, the Super League side's coach, added: "I played back-to-back football for five years and I know what the demands are. Rest is essential. We've had the centenary season and now the summer league, and I want my players to be fully recovered by the time we get back to full training."
St Helens, Warrington's neighbours, have already said that they will not allow their players to play rugby union next winter.
Meanwhile, Warrington have welcomed two new arrivals to Wilderspool: the New Zealand scrum-half Willie Swann and Alliance coach Robert Tew, an Australian. Swann, who played for Western Samoa in last October's World Cup, will make his debut on the substitutes' bench for Warrington's home game against Sheffield Eagles tomorrow.
Salford Reds will be without the Samoan winger Fata Sini for Sunday's First Division visit to Hull after he was banned for one match and fined pounds 75 by the Rugby Football League disciplinary committee. Sini was dismissed during Salford's home defeat of Rochdale Hornets last weekend for tripping.
The Widnes hooker Paul Gartland, sent off in his side's 31-14 victory against Wakefield Trinity, has been found not guilty of a high tackle. The Barrow Braves prop Stuart Quayle, who received his marching orders for illegal use of the elbow, has been suspended for four games and fined pounds 50.
David Chrimes, the Doncaster Dragons second-row forward, was handed a two-match ban and a pounds 50 fine following his dismissal, also for illegal use of the elbow.Reuse content