Swiss driver Simona De Silvestro will have to find a new team if her Supercars career is to continue past this year.
Kelly Racing confirmed on Friday New Zealander Andre Heimgartner will stay with the team for 2020.
Kelly Racing is cutting back from four Nissan Altimas this year to running just two Ford Mustangs next season.
The decision to stick with Heimgartner alongside co-owner Rick Kelly means De Silvestro and Garry Jacobson are both without a seat for next year.
De Silvestro became the first full-time female driver in Australia's premier touring car championship for more than four decades when she signed a three-year deal in 2016.
The 31-year-old recently signed a deal to join Porsche's Formula E program but has said she may yet drive in Supercars next year.
Possible destinations for De Silvestro include an expanded Team 18 under Charlie Schwerkolt while Matt Stone Racing is also expected to expand to two cars next year.
A new Sydney-based team which James Courtney has already committed too is looking for a second driver while Brad Jones Racing could have a vacancy if Tim Slade departs the Albury-based outfit.
Heimgartner has been with Kelly Racing since 2018 and this year is his fourth full season in Supercars, including a podium finish at Phillip Island in April.
"It is important that we future-proof the team and, at only 24, Andre has many years of driving ahead of him," co-owner Todd Kelly said.
"In the last two years, it has been terrific to witness first-hand Andre's development as a driver and with the opportunities ahead next year there's no doubt that he'll be highly competitive in a Mustang."