Russia's forces in Ukraine will be "exhausted" soon, said a former senior NATO leader.
Ukraine is seeking to push back Russian forces along a broad front in east Ukraine.
In an interview with New York radio station WABC 770, Stavridis said that while Ukraine was winning on the ground, Russia had an advantage in the air.
"I don't see either side having a breakthrough moment — at least this winter," Stavridis told WABC host John Catsimatidis.
Ukrainian and Russian forces are fighting along an approximately 600 mile front, with Ukraine forcing Russia into defensive positions in the south and northeast, while Russian forces are seeking to advance around the eastern city of Bakhmut.