The Wales coach was in charge of the Lions for the series win in Australia in 2013 and the drawn series against New Zealand last summer, and has often voiced his concerns about the amount of games involved in a tour.
The Lions played 10 games in a six-week period in New Zealand and are expected to play eight matches in a five-week window when they go to South Africa in 2021.
Talk of shortening the domestic season in order to give the Lions more time to prepare for tours has been shot down by Premiership Rugby chief Mark McCafferty, who claims it would badly damage the competition.
Gatland, who is currently preparing his Wales team for a two-Test series in Argentina, says it is imperative the schedule for the British & Irish Lions is altered to avoid putting the player's health at risk.
"I felt in New Zealand my biggest concern was flying on the Monday, arriving on the Wednesday, and then playing that Saturday," said Gatland, "By doing that we were opening up players to the potential of injury risk.
"My view is that by taking the field as early as we did in New Zealand without adequate preparation, we were doing that. I'm not the only who has said that, everyone has."