Stuart Lancaster has warned Sam Burgess he must serve a successful union apprenticeship if he is to be selected by England, but offered a glimmer of hope that he could be involved at the 2015 World Cup.
Burgess will begin a three-year contract with Aviva Premiership club Bath in October after a release fee was agreed with his NRL team South Sydney Rabbitohs.
So far the move has been funded exclusively by Bath, although Lancaster revealed the Rugby Football Union could yet be involved financially, stating: "I think there are discussions ongoing."
The decision of possibly the biggest name in league to change codes has been greeted with excitement, although Lancaster has denied the 25-year-old will be fast-tracked into the England team.
The suggestion Burgess has been earmarked for the World Cup met with a cold blast of reality from Lancaster as he outlined what it will take to become a dual-code international.
"Sam is going to have to earn the right like anyone else - I've never said he's going to be fast-tracked into the World Cup squad," Lancaster said.
"I had a discussion with Sam's representatives and said there will be no short-cut into the next elite player squad that we announce in January.
"I can't see for one minute that Sam Burgess is going to be in that EPS squad having played two months of rugby union.
"If he earns the right to be an EPS player, he will have to do it the way everyone else has done it, by playing well for his club.
"The reality is that he'll go to Bath as a Bath player and play for Bath in the second half of next season.
"It's going to be extremely difficult for a player to come from rugby league in October and then play in the 2015 Six Nations.
"If he makes the transition smoothly and effectively and begins to play well during the second half of that season, then there is an outside chance he could make the World Cup training squad.
"If he makes the World Cup training squad, there are two warm-up games before the squad is announced..."
Burgess cited the 2015 World Cup when explaining his decision to switch and, at 6ft 5in and over 18 stones, he has the physical attributes needed to make an impact with Bath and England.
Although a forward in league, inside centre appears his most likely position when he begins his career at the Recreation Ground. Number eight has also been mentioned as a possibility.
Lancaster views him in the mould of Sonny Bill Williams, who has represented New Zealand in both codes and helped the All Blacks win the 2011 World Cup as a highly effective impact substitute.
"The closest comparison I can make is Sonny Bill Williams, who was a forward in rugby league but played in the backs in union," Lancaster said.
"When Sam was playing league for England at last year's World Cup, you could see him defending in the back line from set-piece."
While Lancaster has welcomed Burgess' move, describing him as a "great asset", his caution over anointing him as an international in waiting is dictated by a lengthy history of failed code breakers.
Jason Robinson's brilliance shone in both formats, but is the exception when compared to aborted experiments such as Barrie-Jon Mather, Henry Paul, Lesley Vainikolo and Andy Farrell.
However, during a visit to Australia last year, Lancaster met with Burgess - and liked what he saw.
"Sam is clearly a world-class rugby league player," Lancaster said.
"What impressed me more so than his ability to carry the ball, pass and tackle, was his mental toughness and fortitude, his leadership and ability to take on a challenge," Lancaster said.
"For a player to go to Australia at 18 because he wanted to challenge himself at a higher level, and now to challenge himself to get into a World Cup squad within nine months, is tremendous.
"He's leaving as an iconic player in league and having to start from scratch.
"What impresses me is his mental toughness and his leadership. Those are the assets I am excited about the most.
"The bigger the challenge for Sam, the more he rises to it. He raises his game. I liked that trait in people."