Britain's double Olympic champion Mo Farah could attempt a 10,000 metres-marathon double at the 2016 Rio de Janeiro Games, his coach Alberto Salazar said.
Farah thrilled a home crowd at the London Games in August when he became only the seventh man to complete the 5,000-10,000 metres Olympic double.
Salazar told BCC Sport that Farah, who will be 33 in four years' time, could have lost a "little speed" over the 5,000 by then.
"My guess is he will do a 10-marathon double," Salazar said.
"At Rio, that would be a good shot. We will have a look at the schedule but if the 10 is first, he would go 10,000 and marathon."
Farah will attempt to replicate his Olympic double at next year's world championships in Moscow and could then make his marathon debut in the 2014 London race.
"The way we look at it is pretty simple," Salazar said.
"He's the best long-distance runner on the track in the world right now....so why would you go from where you are the best in the world to something completely unknown?
"The only time it makes sense is that he could run the worlds in Moscow next summer and then do London in April, 2014. There is no worlds or Olympics in 2014, so he could run London and then still perhaps run a late track season in August."
However Salazar said there was no guarantee that Farah would move up to the marathon,
"The exception will be if his track running is continuing to go so good that we feel, you know what, maybe he's tried a marathon, but if he's still on top in the 5,000, why would he go to marathon?," he said.