He will hand over the reins on the ground to his assistant Clarke Dermody, although he acknowledged the situation was far from ideal.
"Having to head to Japan earlier than expected is disappointing particularly leaving my team before the end of the season, it's not what anyone would have wanted," Brown said.
"I will be in touch with Clarke and the other coaches on a daily basis and I am positive they will respond well to the situation."
Tony Brown is heading back to Japan. Photo / Photosport
The disrupted nature of Japan's preparation for this historic match, due to the pandemic over the last 12 months, has meant they have not spent time together as a team since 2019.
Brown said the uncertainty created by the pandemic had forced the Japanese side into a condensed period of preparation for the match.
"Even though the Lions match has only recently been finalised it's unfortunate that the Japanese preparation has been so limited we will need to go into an intense camp almost immediately to get organised."
Highlanders CEO Roger Clark is taking a pragmatic approach to the disruption.
"No one could have predicted it would come to this, due to the pandemic the Lions tour itinerary has been completely up in the air for the better part of a year,'' Clark said.
"The way it has worked out means Brownie's international obligations suddenly overlap with his Super Rugby duties, which obviously is a situation that doesn't sit comfortably with anyone.
"However, as an organisation we know we still have his services even though he is not on the ground with us, we have every faith in Clarke and the coaching and management group to deal with the challenge."
Highlanders talent development coach Kane Jury will join the coaching team for the remainder of the season.
