Sir Mo Farah is considering a return to the track to defend his 10,000m title at this year's World Championships.
Britain's four-time Olympic gold medal winner called time on his glittering track career in 2017 to concentrate on marathon running.
But the 35-year-old has given the clearest indication yet he is weighing up a comeback in Doha this autumn.
Farah will run in the Vitality Big Half marathon in London on Sunday as part of his build-up to April's London Marathon.
Farah has confirmed that should he tick the box in winning around the streets of the capital, then competing at the World Championships in the 10,000m - rather than the marathon - is a genuine possibility.
"It all depends on the result in London," said Farah.
"Having seen my fellow athletes, who I've competed against in the past, and watching the European Indoor Championships on TV, I was thinking 'Oh man! I want to get back out there'.
"I miss the sort of atmosphere Laura Muir got. You get it at the London Marathon but I do miss the track. I do miss representing my country.
"That's just me. If things are going well and I've got a chance to win a medal, then I'd love to come back and run for my country but my aim now is to concentrate on the marathon."
Farah added: "My aim is to win London one day. I think if I can win it, at least you know you've achieved it.
"That would be another way of going back to the track, seeing what you can do. My aim is to do well in London but if it doesn't go well, then I don't know."
Farah turned his back on the track after winning a third consecutive 10,000m gold at the World Championships in London two years ago.
"I had said to myself that I wanted to finish in London," he added. "I was thinking 'I just want to do marathons and it's going to get easier'. It's not easier.
"But seeing the (10,000m) results, it hasn't really changed. The athletes doing well are 1500m indoors, the mile but in terms of long distances, it hasn't really changed much, and now part of me is thinking 'Have I still got it?'."