Serena Williams has withdrawn from the women’s doubles event at Wimbledon due to a right knee injury, ending her planned meeting with sister Venus Williams at the tournament.The 44-year-old suffered the injury during her singles comeback earlier this week, where she lost a three-set match.Announcing her retirement in an Instagram post, Serena wrote: “I am heartbroken to have to retire from doubles. Returning to compete again was a gift, and the opportunity to play alongside Venus Williams once again meant the world to me. I did everything I could, but unfortunately my knee is not ready to compete.”Along with the post, Serena shared photos of four syringes, saying they showed “the fluid they drained from my knee after my singles match.” She also posted a video of herself walking with heavy strapping on her right leg, while one of her daughters appeared to be carrying a cane for her.Despite the setback, Serena suggested she could return to competition soon, with the US Open looming.“All I can say,” Serena added, “is stay tuned to a city near you.”The Williams sisters were scheduled to face Camila Osorio and Solana Sierra in the first round. Their match was the only first-round women’s doubles contest not played earlier in the week, after it was delayed to give Serena more time to recover.Serena was back in singles action on Tuesday, but was beaten 6-3, 6-7(6), 6-3 by 20-year-old Maya Joint of Australia.Venus also featured in the mixed doubles event on Friday alongside Kevin Krawietz. The pair lost in straight sets to Tereza Mihalikova and Lloyd Glasspool.The Williams sisters have won six Wimbledon women’s doubles titles together.