Cassidy revealed ahead of the start of the 2020 Super Formula campaign that he would be bowing out of the series after securing a FE seat with Envision Virgin Racing for 2021.
The New Zealander had initially hoped to combine his new role with a full- or part-time campaign in SUPER GT with TOM'S, but ongoing uncertainties with travel restrictions due to the global health crisis have put paid to those ambitions.
However, Cassidy has not ruled out the prospect of one day returning to either Super Formula or SUPER GT alongside FE if the conditions are right.
He pointed to the example of former Mahindra FE racer Felix Rosenqvist, who was able to dovetail his drive in the all-electric series with a season in Super Formula in 2017 and then a SUPER GT campaign the following year, both with Team LeMans.
"I always wanted to keep racing in Japan and combine racing in Formula E with racing in Japan," Cassidy told Motorsport.com. "But the thing that makes that difficult now is travel.
"I hope when the situation with travel changes, I'm able to come back. I want to leave that possibility open because I've enjoyed my time here.
"I look at someone like Felix Rosenqvist, he was able to do both Formula E and Super Formula or SUPER GT. It seems like the perfect programme."
Nick Cassidy（VANTELIN TEAM TOM'S）