Rossi want's to join Americas' primer open wheeler series, while Chilton has some offers in DTM and LMP1.
F1 test driver Alexander Rossi is looking to switch to America's premier open wheeler series Indycar for 2015.
Although Californian, the 23-year-old has risen through the European racing ranks over the past six years, including in Formula BMW, the Renault world series and finally GP2.
This year, he came tantalisingly close to his elusive F1 race debut, initially with a role at Caterham and then at Marussia where he almost replaced Max Chilton amid the British driver's sponsorship problems.
But as those backmarker teams struggle now for mere survival, racer.com says Rossi has now set his sights on Indycar.
"I've come back to the US," he announced this week, "and I'm concentrating my efforts on Indycar next year."
Out of control
He revealed that almost replacing Chilton in the Marussia race seat at Spa was not his only close encounter with the Grand Prix grid during his F1 career.
"No, I didn't take a Grand Prix start," said Rossi, "but people may or may not be aware of the fact that I was called to race for Marussia five times this year and for circumstances that were out of my control - and financial reasons that were in the news - it didn't work out.
"The trust and faith the team placed in me and Formula One placed in me as an American was always there, but with financial issues rendering two teams inoperable and four seats vaporising, landing a seat has become very difficult," he added.
Rossi revealed that he has been in talks with Indycar teams "for a while".
DTM or LMP1?
It appears Chilton is another victim of the Marussia demise, and the 23-year-old said he is also now turning his mind to opportunities outside of F1.
"I've already started looking," Chilton told Sky, "and I've been given some offers in DTM and LMP1.
"It's great to be offered them, but obviously I'm a Formula One driver and I want to make sure I get there. So that's plan A at the moment.
"Plan B, I might have to start to revert to pretty soon because obviously seats are going to go, so I don't want to kind of shoot myself in both feet," he admitted.
"It's going to be an interesting couple of weeks and hopefully we come out with the result we want," added Chilton, who said a F1 reserve role for 2015 also cannot be ruled out.
"If that reserve role would maybe give you a possibility of a race seat then I might take it, but I think at this moment in time Marussia's (survival is) my best bet."