But he has welcomed the challenge and wants to see as many England internationals as possible jetting Down Under, citing the benefits of being part of the Lions set-up to a player's development.
"I have talked about the Lions tour with the players and my message was that we want to see as many of you as possible to get on the Lions tour," said Lancaster following a three-day England training camp.
"It is a massive thing for a player and it helps their development, it helps them become better players if they are able to go and represent England within the Lions at the highest level.
"I want the players to feel we are behind them and supporting them and when I talked about their journey I made specific reference to the Lions.
"I don't want to say, 'Actually, we'd like to keep you back for Argentina', I want to try and get as many players as possible on that tour then I can take some developing lads to Argentina.
"The following year we are all off to New Zealand on tour and we need to make sure we have the experience for that challenge."
Lancaster may also have to contend with the temporary loss of some of his back room staff. Graham Rowntree was a part of Sir Ian McGeechan's coaching party during the 2009 tour of South Africa.