The 18-year-old prospect had her application to play denied by the National Collegiate Athletic Association, despite her not even being at college yet.

Potter has committed to her college ambitions with UCLA, but her visa application has been delayed amid the COVID-19 pandemic.

But the NCAA's ruling means Potter will be unavailable to play this season, with college students only allowed to participate in amateur leagues.

Canberra unveiled on Tuesday morning it had signed former Adelaide Lightning guard Hannah Kaser to offset Potter's departure.

Capitals coach Paul Goriss was disappointed to farewell Potter, but wished her well in the United States.

"Gemma was a fantastic contributor to our championship last year and whilst I'm disappointed she can't be with us for the upcoming year, I wish her great success at UCLA," Goriss said.

"I hope we see her in Caps colours again one day."

Kaser has trained with the Capitals for two weeks, linking up with Canberra Nationals teammate Abby Cubillo.

The 27-year-old guard has been part of the National's squad for two years, helping them to the 2019 Waratah League final.

Kaser made her WNBL debut last season with Adelaide, following a stint with St Mary's College in California.

The Victorian native is relishing the opportunity to aid the Capitals' tilt for a historic three-peat over the next two months.

"I'm very excited to be joining the Capitals for the 2020 season," Kaser said.

"Any time you can have an opportunity to join the two-time defending champions, particularly when they are located in the place you call home in the off-season, it's something you have to jump at."

The Capitals will join their WNBL rivals in a north Queensland hub in the coming weeks, with the 56-match regular season to start on November 12.

Goriss was pleased to have Kaser on board for one of their most challenging campaigns yet.

"Hannah is a great player and a fantastic person so she will fit in really well with our group," Goriss said.

"I have had my eye on her for the past couple of years and to finally get her here is very exciting. She plays with great energy and you can never have too much shooting."