Nick Cassidy will miss the final two rounds of the Super GT season with TOMs announcing Kenta Yamashita will replace the Kiwi in the No.37 Toyota GR Supra.
Cassidy was second in the championship with co-driver Ryo Hirakawa, one point adrift of leaders Kazuya Oshima and Sho Tsuboi.
However, the 2017 series champion flew to Italy last week for a private test at the Magione circuit with his new Envision Virgin Formula E team.
Quarantine restrictions now mean Cassidy will have to sit out this weekend’s penultimate Super GT round at Motegi Raceway.
He will also skip the finale at Fuji as the date clashes with the official Formula E pre-season test in Valencia.
The test will be one of the last opportunities for Cassidy to get up to speed in the all-electric formula. Because Envision are a customer team to Audi, it is allocated very few private tests outside of the official pre-season dates before the start of a new season.
Yamashita is the defending Super GT champion and will be a welcome addition to Hirakawa who will now pursue the title solo.
Fortunately, Yamashita has experienced the 2020 Supra when he subbed in for Heikki Kovalainen at the season-opener in Fuji.
Cassidy should still be able to compete in the next Super Formula event at Autopolis on November 15.
However, he will then be forced to miss the next two rounds at Suzuka in early December as he will be obligated to undergo another two-weeks isolation when returning from Valencia.
Given how tight the current Super Formula championship is at the moment, Cassidy will have his title-defence hopes all-but ended when he sits out both Suzuka races.