Safina, 25, has not played since early May because of persistent back pain. She announced in August that she would not play again this year.
But brother Marat said she had quit for good.
"If you recall, Dinara first suffered the injury in Beijing two years ago," the former men's world number one was quoted as saying on Saturday by Russian media.
"She had tried several times to make a comeback but it only caused her more problems.
"Now she must think of herself, not if she could play again, but just to live a normal life. She must continue with her therapy, but would not be able to play again.
"She will make an official announcement, but being her brother, I think she has no chance at all of making a comeback."
(Reporting by Gennady Fyodorov; editing by Timothy Collings)