The Spaniard competed in the Indianapolis 500 this year, missing the Monaco Grand Prix, but has ruled out an immediate return.
Indianapolis, Le Mans and the Formula One world championship make up the so-called ‘Triple Crown’ of motorsport, a feat achieved only by the late Graham Hill and one that Alonso wants to match.
“I’m still thinking, still deciding. I could have a decision already made, but there’s still some details that we need to figure out,” Alonso said in an Instagram Live Q+A when asked about his F1 future.
“My aim is to be the best driver in the world, the most complete driver in the world and for that, you need to win in different series in different cars at different times.
“The Triple Crown is still a very big priority for me, so I’m working on that. I think it’s going to be a very exciting 2018 season for motorsport fans,” added the double world champion.
The 2018 Indycar calendar was published on Thursday, with the Indy 500 again clashing with Monaco on May 27, and Alonso said he had taken a look.
“I think the full championship is something not in the short term that I’m thinking,” said Alonso. “The Indianapolis 500 is something very attractive that I will do in the future. I don’t know when that future will be but I would like to have another try there.”
Alonso, who retired from this year’s race with an engine failure after leading, will wear his Indy 500 helmet design again at next week’s U.S. Formula One Grand Prix in Austin, Texas.
Next year’s Le Mans on June 16-17 does not clash with Formula One and comes between Canada and the French Grand Prix at Le Castellet.
With champions Porsche pulling out of Le Mans as a works team, Toyota are set to be the only major manufacturer in the top LMP1 category if they decide to continue.
Toyota would not have been an option for Alonso while McLaren were partnered by Honda but that relationship is ending with the British-based team switching to Renault engines.
Toyota have said they are always willing to talk to top drivers, while McLaren have indicated they could let the Spaniard race at Le Mans for another team.
“If it is something he would like to do, in the right circumstances, we would be open to that,” McLaren executive director Zak Brown said last month.
(Reporting by Alan Baldwin, editing by Christian Radnedge)