Fernando Alonso said he needed time to look into McLaren's new partnership with Renault before pledging his future, as he kept his options open despite their split with Honda.
Alonso repeatedly threatened to quit as McLaren struggled with their Honda engines, and their switch to Renault power next year is expected to convince him to stay.
But the two-time world champion, who has also dabbled in IndyCar, said he first wanted to study the new partnership, which was announced at the Singapore Grand Prix on Friday.
"I just received the news and now after Singapore, which is the first priority for me, I will try to know a little bit more about the project and about the Renault engine, about the expectations for next year," Alonso said.
"Because obviously right now I don't know anything. So after I consider that I will make decisions."
The 36-year-old Spaniard said earlier in Singapore that he had offers both inside and outside of F1, and that he would make up his mind in the next few weeks.
Alonso, who won his world titles with the Renault team in 2005 and 2006, has a long-term goal of becoming only the second driver to complete the Triple Crown -- winning the Monaco Grand Prix, Le Mans and the Indy500.
Securing his services is a major priority for McLaren, who are Formula One's most successful British team but have not won a race since 2012.
"We're going to turn our attention to Fernando now," said McLaren executive director Zak Brown. "We've been speaking a lot... I think in the not-too-distant future we should be able to get something done.
"And that will be the last big piece of the puzzle."
Switching to Renault might not be the catch-all solution for McLaren as, like Honda, the French engine-maker has also had its problems with F1's complex hybrid technology.
"McLaren have gone from the fourth-worst engine to the third-worst engine," commented Sky Sports analyst and ex-F1 driver Martin Brundle.
Alonso also sounded a note of caution when he said: "You never know if it's a good move or a bad move for the team.
"But I think definitely if McLaren thought it was time to split with Honda and go for Renault, it's because they have good information about next year.
"Hopefully that will put McLaren again in the places that we all feel that McLaren belongs."
Alonso added that he felt "proud" of McLaren's project with Honda, despite the fact it has failed to yield a single podium place in more than two-and-a-half seasons.
"We all felt that it was the perfect match, we all felt that this could be a great time for this partnership," he said.
"Unfortunately, we tried our best and we didn't succeed."