NEW YORK—Players’ mental health is in focus as the U.S. Open kicks off Monday after four-time Grand Slam winner Naomi Osaka led the charge for her fellow athletes this year. The 23-year-old withdrew from the French Open after being fined and threatened with expulsion for refusing to attend media conferences, which she said had an adverse impact on her mental health, and disclosed she had suffered from depression for years. The incident led Roland-Garros organizers to concede that the sport’s governing bodies needed to do better and the United States Tennis Association (USTA) this week announced a mental health initiative for players in partnership with the Mount Sinai Health System. “Sports psychology has always been in the realm of, ‘how do we optimize on the court?’ but there’s so many reasons for why athletes are impacted after competition,” Shannon O’Neill, Ph.D., a psychologist at Mount Sinai West, told Reuters. “Really …