Legislative aides say Senate Democrats are considering cutting International Monetary Fund (IMF) provisions from a bill providing aid to Ukraine and authorising sweeping sanctions on Russia.
The move would be a significant retreat from Democrats.
The Obama administration, too, has argued IMF reforms are critical to congressional legislation responding to Russia's annexation of Crimea.
Aides say the change will be discussed by the entire Senate Democratic caucus on Tuesday.
They were not authorised to speak publicly on the matter and demanded anonymity.
The Senate advanced a bill on Monday including language enhancing the lending capacity of the IMF in a commanding 78-17 procedural vote. But House Republicans remain opposed.
Lawmakers on both sides are growing increasingly embarrassed by the lack of action by Congress more than two weeks since Russia's military incursion.