Graham Henry believes the British and Irish Lions could pay the price for a "suicidal" schedule on their tour to New Zealand.
Warren Gatland's men will play 10 games in just over a month when they make the trip to the southern hemisphere.
The Lions face six matches before the first of three Tests against the All Blacks at Eden Park on June 24.
Former New Zealand and Lions coach Henry thinks the itinerary is asking too much of players who will be going into the tour on the back of a long season for club and country.
"I know from my own experiences how much the players respect getting selected for the Lions. It is the pinnacle of their career. It is massive but they need to do well and I just wonder if the itinerary is suicidal. That is my concern." he told ESPN.
"They are playing New Zealand Maori, they are playing the five franchised teams - and those five franchised teams have nothing to lose, no pressure on them at all, so they will fire everything at the Lions and take them on.
"Hopefully they have the ability to overcome that. But really when you tour, you need to ensure some momentum is created by results and you just wonder how they are going to go into the Test series with that itinerary. It is very demanding."
Henry added: "They are remembered by the Test match results but sides gain confidence and momentum through the games they play leading into those Test matches and if they don't get success in those games, confidence is not going to be high and that is going to affect the way they play in the Test matches,
"I don't know if you can draw a line between the games you play prior to the Test and the Test. I think it is all part of what you're doing there and part of the psyche of the team, the confidence of the team and how they play.
"Certainly they are going to be remembered for how they play in those three Tests, but the building of the confidence and the ability to play the game through those franchise games and the New Zealand Maori game will be pretty important."
Gatland names his squad for the tour on Wednesday.