Like suspended member Williams, Force India has broken ranks with the FOTA teams' alliance and unconditionally signed up to contest the 2010 world championship.
The move, reported by Germany's Auto Motor und Sport, leaves just eight current teams, including top outfits Ferrari and McLaren, threatening to sit out next season over the budget cap rules dispute with FIA president Max Mosley.
The eight teams have no official meetings planned for Istanbul, but Ferrari team boss Stefano Domenicali was on Thursday spotted entering the FIA motor home for a sit-down with Mosley's representative Alan Donnelly.
The Italian then moved on to the McLaren building. Mosley, and the FOTA chairman Luca di Montezemolo, are not in Turkey this weekend.
Auto Motor und Sport said that Brawn GP, which like Williams and Force India is an independent outfit that would welcome the budget cap's cost-limiting function, is not going to also defect.
"The recent proposal of the teams makes a great many concessions to the FIA," Ross Brawn is quoted as saying. "The result would be the same as Mosley's budget limit."
BMW's Mario Theissen on Thursday agreed that the proposal is similar to the budget cap, although the 'name' would have to change.