Warren Gatland would have to take a year off from his Wales role if he were to succeed Ian McGeechan as British and Irish Lions coach in Australia in 2013.
Gatland has a five-month break clause in his Wales contract that could give him the chance to be part of the Lions party.
Lions team manager Andy Irvine insists they have yet to settle on a coach.
He added: "We would be looking for the coach to be available effectively a year out."
If chosen from the four home unions, that would rule the Lions coach out of any involvement in a nation's 2012 November Tests or the 2013 Six Nations that follows.
In October 2010 Gatland signed a contract extension with the Welsh Rugby Union that sees him in charge until after the 2015 World Cup.
That deal includes the five-month break from Wales duties, which Gatland stated at the time was to give him the chance to spend time at home in New Zealand.
However, the timing of the break in his contract coincides with the Lions tour schedule.
The choice of Lions coach will be announced after the 2012 Six Nations and would be allowed to undertake summer 2012 tour duties.
Wales play three Tests in Australia in June 2012, while Scotland also face the Wallabies before heading for the Pacific Islands.
At the same time Ireland take on World Cup holders New Zealand and England travel to South Africa.
Irvine added: "I think it's fair to say that if any of them [national coaches] are involved in summer tours we would regard that as acceptable, but that thereafter we would be hoping that he could concentrate entirely on the Lions."
England have yet to name a new coach following Martin Johnson's decision to step down amid the on-going fall-out from their unhappy World Cup campaign.
McGeechan, now in charge at Bath, could also be a candidate to lead a fifth Lions tour having done so in the 1989 tour success against the Wallabies and the series defeat against New Zealand in 1993, 2-1 win in South Africa in 1997 and the 2-1 defeat by the Springboks in 2009.
Former Scotland coach and player McGeechan had Gatland and his Wales assistants Robert Howley, Shaun Edwards and Neil Jenkins in his back-up staff in 2009 along with England's Graham Rowntree.
Irvine says that as one of four men who will choose the 2013 Lions coach, he cannot rubber-stamp anyone for the role.
"We have a completely open mind for the 2013 tour on who it [the coach] will be," said Irvine.
"Whoever the coach is will be taking a year out. He does not have to come from the home unions and we could look worldwide, but ideally the head coach will come from a union associated with the Lions."
But he conceded Gatland is one of the leading candidates in the wake of Wales' strong World Cup campaign.
"There is no doubt that Wales had a hugely successful World Cup," said Irvine.
"And what impressed me so much was the way that they got their selection right.
"They managed to bring through some youngsters, some exciting youngsters and they were very good off the field of play.
"And I have to say I think they were unlucky and with a modicum of luck they could have well been in the final and who knows?
"They were playing so well they could have really challenged New Zealand.
"And so fair credit to Wales, a super World Cup and great to see."