"If FIFA succeeds in reforming itself -- and in my view they're making good progress here -- then we will continue," Adidas chief executive Herbert Hainer told the business daily Handelsblatt.
Adidas has sponsored FIFA for more than 40 years and the current contract runs until 2030.
But if FIFA fails to get its house in order, "we will have to think about what the alternatives are," Hainer said.
FIFA chief Sepp Blatter has been suspended by the organisation he has headed for 17 years, and faces a hearing at the ethics committee over allegations of corruption.
More From This Section
While a number of other major sponsors, such as Coca-Cola and VISA, have called on Blatter to go, Adidas has so far taken a more conciliatory tone.
He rejected suggestions that Adidas might have known about the shady wheelings and dealings going on within FIFA.
"No-one can claim Adidas is responsible," he said.