Serena Williams has added herself to the list of big-name withdrawals from the U.S. Open. She pulled out of the year’s last Grand Slam tournament because of a torn hamstring. Williams announced her decision in a social media post. She hasn’t competed since injuring her right leg during her first-round match at Wimbledon in late June. The American joins Roger Federer and Rafael Nadal in sitting out the competition in Flushing Meadows. Williams owns 23 Grand Slam titles. The American turns 40 next month. The draw for the U.S. Open is Thursday. Play begins next Monday.