Naomi Osaka (24) committed next month's tournament in San Jose, California, her first appearance since a first-round loss at the French Open on May 23.
The four-time Grand Slam winner accepted a wildcard entry into the Mubadala Silicon Valley Classic on Monday.
Osaka, 24, withdrew from Wimbledon due to a nagging injury to her left Achilles.
The San Jose tourney begins on Aug. 1. Osaka joins a field that includes Wimbledon champ Elena Rybakina, World Number five Ons Jabeur and American teenager Coco Gauff as they all continue their preparations for the upcoming US Open in New York.