British and Irish Lions manager John Spencer has revealed that only a head coach able to take a year-long sabbatical will be considered to lead the 2017 tour to New Zealand.
The successful candidate and his assistants will be appointed by the board towards the end of the summer upon completion of the home nations' visits to the southern hemisphere in June.
Spencer, speaking at the announcement of Standard Life as the Lions' principal partner, insists fortunes over the next six months will be pivotal to the decision.
"We have always had a totally open mind about the appointment and still have. We have one Six Nations and a summer tour to go and a lot can happen," Spencer said.
"We look at the form of coaches in the same way as the players are examined. There is a long time to go yet.
"We could well look outside the Six Nations, but I haven't heard of any proposals for that at the moment.
"We would expect them to give 100 per cent of their time to the Lions. That would be the best preparation and we are looking for best principles."
Wales head coach Warren Gatland was at the helm for the triumphant 2013 tour to Australia, but Spencer refuses to view the Kiwi as the favourite.
"I couldn't say if Warren is in a strong position. We have to keep an open mind until the last minute and look at teams in the Six Nations and summer tours," Gatland said.
"He has obviously been very successful. As far as the New Zealand tour is concerned it is a blank sheet. Everyone has to have a first tour.
"If you get into the lions culture and values you can understand it pretty well from scratch."
Recently-appointed England head coach Eddie Jones is an outsider, according to Spencer. "I think it would be unusual for a coach who has just come in to be suddenly considered for the Lions," he said.
"I'm not sure [Rugby Football Union chief executive] Ian Ritchie would talk to me very favourably if we suddenly asked him for a 12-month sabbatical after a couple of months in office. But anything can happen."