Safin told Russian sports agency R-Sport on Friday that the 25-year-old Safina considers her decision "as a next step in her life."
In May, Safina took an indefinite break from tennis in hopes of recovering from chronic back pain, but was pessimistic about her chances of returning. She said at the time she didn't want to "torture myself and my body any longer."
"She can live a daily life, but can't do sports anymore," Safin said.
Safina turned pro in 2001 and won 12 titles on the WTA Tour. She first became No. 1 on April 20, 2009, and spent 26 weeks at the top of the rankings. She injured her back early in 2010 and dropped out of the top 20 by the end of the year.
Safina won silver at the Beijing Olympics in 2008 and lost in three Grand Slam finals.
Her brother said it was not clear what his sister will do next.
"An athlete has lived with sports for 20 years. Now she needs a year to pull herself together, then she will decide," Safin said. "She is only 25 and there's no need to hurry her."
Safina and Marat, who was No. 1 in 2000 and retired in 2009, are the only brother and sister in tennis history to reach No. 1.