The American signed a one-year deal in February to race in IndyCar in a joint Andretti Autosport/Bryan Herta Autosport entry, going on to steal a shock Indy 500 win, after missing out on an F1 race seat with Manor.
He is having discussions about full-time 2017 deals with Manor, with which he holds a reserve role this year, and one other F1 outfit.
There are also opportunities in IndyCar, with Andretti the frontrunner.
"I have options both in IndyCar and Formula 1 for 2017," Rossi told Autosport.
"There have been talks with Manor for a race seat and we've also been approached by another F1 team that's quite interesting.
"There are options in IndyCar that I can't elaborate on, but I can say Andretti and I have a great working relationship.
"Everyone at Andretti is aligned and working in good faith to extend our deal for several years.
"There's a sense of loyalty to Michael [Andretti], his team and Honda.
"As a driver there are some really good opportunities here and the competition is fantastic."
As part of his reserve deal, Rossi was to be offered the opportunity of a race seat should it become available this year.
An offer was made in Hungary to take over Rio Haryanto's seat for the remainder of the season as the Indonesian requires more investment.
But the final three IndyCar races on the schedule clash with F1 grands prix, and as his American programme takes priority, Rossi declined Manor's offer.
"My management and I are in constant communications with Manor and we knew there might be an opportunity to race for the last half of the 2016 season," he said.
"We gave it careful thought but declined the race seat due to my IndyCar contract.
"I have a lot of respect for Manor giving us first right on the seat as we agreed.
"I have a really good relationship at Manor and there are no hard feelings.
"They understand an F1 deal has to be right for my future and my career has taken some good steps forward."
Rossi retains dreams of returning to F1 but insists any deal must be right for his long-term future.
"Last year I did a partial F1 season, which was very successful," said Rossi, who contested five late-2015 grands prix for Manor alongside his GP2 campaign.
"When I didn't get the full time seat in 2016, this created a 'Y' in the road where now I cannot take that risk again.
"I've invested most of my career in F1 and I would love to continue but as I've said all year, an F1 deal must be right."