Players should not be penalised because of the "decisions of an authoritarian leadership", the head of the Women's Tennis Association says.
Steve Simon says he "feels very very strongly" that players from Russia and Belarus should be able to continue to compete on tour.
They are not currently allowed to play under their country's name or flag, or play in any team competitions.
"You never know what the future may bring," Simon told BBC Sport.
"But I can tell you that we have never banned athletes from participating on our tour as the result of political positions their leadership may take.