The Widnes winger, crucial to their chances against St Helens at Central Park, is the man who has spanned a gap that once seemed unbridgeable. Not only is he by far the most valuable player on Widnes' books he is also the jewel in the crown of Sale rugby union club.
The deal that will see the two codes share his services gives Devereux a special place in rugby history. A number of clubs and individuals have toyed with the idea - indeed, no week goes by without new rumours of the barricades being crossed - but only Widnes and Devereux have taken the bait.
When he finishes his summer season with Widnes, he will pick up the threads of a union career that were severed when, in traditional manner, he came north from Bridgend in 1989.
"I suppose that makes me a bit of a pioneer, but I don't think it has got the media coverage it deserves," he said. "If it had been Jonathan Davies or Martin Offiah it would have been front-page news. But it's John Devereux and it has gone largely unnoticed."
The arrangement, which he describes as "giving me something to look forward to in the cold winter months", came about after Sale - always a club with a healthy respect for league - made a generalised approach to Widnes.
The Widnes coach saw the chance to defray the cost of keeping Devereux at a club which has lost its financial muscle. And, by improving Devereux's finances, Widnes stand to benefit from having a more contented player on their books.
Devereux, who played and toured with the Sale player-coach, Paul Turner, during his union days, is looking forward to his return to his old code in September. Those thoughts are, however, strictly on the back-burner during another six months of league, starting with today's semi-final. "I don't have any problems keeping the two separate," he said. "It's just like closing one book and opening another."
The plot of today's book is generally presumed to consist of St Helens taking the one remaining step to Wembley. Widnes are, after all, a mere shadow of their old selves, stuck outside the Super League elite in the First Division, and Saints, with Wigan out of contention, are obvious favourites to lift the trophy.
The trouble with that argument is that, when Cup rugby is on the agenda, Widnes can rediscover much of their old potency. That has been evident during this season's Challenge Cup run, but even more so when they went agonisingly close to beating Wigan in the Regal Trophy.
"That has to help our confidence going into this game," Devereux said. "Nobody expected us to live with Wigan, but we took them right to the limit that day. We showed we can still compete at that level."
Widnes have had a demanding Challenge Cup draw, including away ties at two of the game's more inhospitable grounds, Workington and Hull. It was at the former that Devereux showed that he has lost none of his attacking flair, going 70 yards for a try that effectively won the match. In the quarter-final at The Boulevard, it was a relentless defensive performance that kept Hull scoreless and probably points to the way Widnes must go about their job at Central Park.
"But we are under no pressure," Devereux said. "We have already exceeded all expectations by getting this far, but St Helens expect to go on and win it - so all the pressure is on them."
There will be pressure of a different sort on Devereux when he becomes rugby's first time-share player. League people will scrutinise him on his return from Sale for signs of weariness or, maybe worse, of bad habits picked up from union.
Not surprisingly, he is firmly of the view that one activity will benefit the other. "We should get away from this idea that rugby players play for a few months of the year and put their feet up for the rest of the year. Pre-season training can be a lot harder than playing matches."
There are a lot more matches to play before Devereux starts that other season. Widnes need him to be all rugby league player against St Helens.Reuse content