In June, United States Tennis Association president Katrina Adams said the US Open would revise seedings to take into account the effect of pregnancy on the current rankings of players.
As such, Williams, 36, still is on course to face a top-16 seed in the third round in her first Open as a mother.
Venus, seeded 16th this year, has a first-round matchup against wildcard Svetlana Kuznetsova, a victor in NY in 2004.More news: Trump's claim on South African farms off mark
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It was another instance of personal matters intruding on the tennis court in a way they never have before, with Williams opening up about her struggles with postpartum emotions since the birth of her daughter, Olympia, in September 2017 and with the feelings of inadequacy that many new mothers experience.
Kuznetsova was given a wild-card entry for the tournament, where main-draw play begins Monday. Wawrinka, a three-time major titlist, eliminated Dimitrov in the first round at Wimbledon in June. The issue arose when Williams - a 23-time major champion and former No. 1 - was not seeded when she returned to action at the French Open in May, her first Grand Slam tournament in almost 1 1/2 years.
Besides Federer-Djokovic, the other possible men's quarterfinals are Nadal-Anderson, Del Potro-Dimitrov and Zverev-Cilic.
"We could not be more thrilled to have added Serena Williams to the lineup of influential speakers" said Leslie Stiles, board president of the Pennsylvania Conference for Women.
Potential women's quarterfinals include Halep vs. No. 6 Carolina Garcia.