Serena Williams is entered and plans to play in the Collector Swedish Open, tournament director Nina Wennerstrom told ESPN via email Friday.
The Swedish Open begins July 14 at Bastad, Sweden.
Interest has been heightened since Williams, acting disoriented and listless, retired from her Wimbledon doubles match with sister Venus Williams on Tuesday.
Serena, who lost in the third round of singles Saturday, looked out of sorts from the moment the pre-match warm-up began. It was an odd scene, as the 32-year-old American had trouble collecting tennis balls from the ball kids and whiffed on some practice strokes.
The start of the match then was put off for about 10 minutes while Serena sat in her sideline chair and was examined by medical staff, including a check of her blood pressure. At one point, Serena hunched over and covered her face with her hands.
"I am heartbroken I'm not able to continue in the tournament," Serena said in a statement. "I thought I could rally this morning, because I really wanted to compete, but this bug just got the best of me."
Serena and Venus have won 13 Grand Slam titles together, including five at Wimbledon. In singles, the No. 1-ranked Serena owns 17 major titles, the most among active women.
The Associated Press contributed to this report.