Williams and sister Venus?will play for the United States when it opens defense of its Fed Cup crown against the Netherlands in Asheville, North Carolina, on Feb. 10-11.
World No. 9 CoCo Vandeweghe also will play for the Americans, whose fourth member will be announced next week.
Serena Williams hasn't played a pro event since last year's Australian Open. In April, she announced that she was pregnant.
Williams gave birth to her daughter, Alexis Olympia, in September. She played in an exhibition tournament in late December in Abu Dhabi before announcing she would not play in this year's Aussie Open.