(Reuters) - Serena Williams, who sat out the U.S. Open due to a torn hamstring, was not on the entry list released on Wednesday for next month's BNP Paribas Open in Indian Wells while Naomi Osaka was one of five former champions entered in the women's draw.

While four-times Grand Slam champion Osaka was on the entry list for the Oct. 4-17 hardcourt event, her participation remains in doubt given she said last week that she would be taking a break from tennis to concentrate on her mental health.