Farah followed up his 5,000m and 10,000m winning performances at London 2012 with gold medals in the same events at this year’s World Championships in Moscow.
But he now seems likely to resist the temptation of continuing his domination in Glasgow next summer and instead concentrate entirely on his marathon debut.
“Glasgow is a bonus if I do it, but it is not on my list,” said Farah.
“My aim is to do the London Marathon and that is what I am fully focused on. I’ve got to come off the marathon healthy and then I’d make a decision.”
Farah was believed to be targeting a world record sub-two hour time for his marathon debut, an aim Lord Sebastian Coe deemed “ambitious”. However, the 30-year-old was keen to clarify those claims did not come from him.
“The rumours started because my sponsors Nike are working on a show called the Sub Two-Hour. I never actually said it,” Farah added.
“I don’t think [two hours] is going to be broken in the next 10 years or even beyond that, maybe even 100 years, because if you think about it, it’s really difficult.”