Serena Williams has withdrawn from the women’s doubles competition at Wimbledon after sustaining a right knee injury, ending her anticipated reunion with sister Venus Williams.

The 44-year-old announced her decision on Saturday, saying the injury she suffered during her singles return earlier in the tournament had not healed sufficiently for her to compete.

“I’m heartbroken to have to withdraw from doubles,” Serena wrote in an Instagram post. “Coming back to compete again has been a gift, and the opportunity to play alongside @venuswilliams once more meant the world to me. I did everything I could, but unfortunately my knee just isn’t ready to compete.”

The post included photographs showing four syringes that Serena said were used to drain fluid from her knee following her singles match. A video accompanying the post showed the 23-time Grand Slam singles champion walking with heavy support on her right leg while one of her daughters carried a cane beside her.

Despite the setback, Serena suggested her return to competition may not be far away as preparations continue for the upcoming US Open.

“All I can say,” she wrote, “is stay tuned to a city near you.”

The Williams sisters, who have won six Wimbledon women’s doubles titles together, had been scheduled to face Camila Osorio and Solana Sierra in the opening round.

Their match was the only first-round women’s doubles contest delayed until later in the week, allowing Serena additional time to recover from the injury.

Earlier in the tournament, Serena returned to Grand Slam singles competition but was defeated 6-3, 6-7 (6), 6-3 by 20-year-old Australian Maya Joint.

Venus, 46, also competed in the mixed doubles event, partnering with Kevin Krawietz. The pair lost in straight sets to Tereza Mihalíková and Lloyd Glasspool on Friday.

Although their latest Wimbledon reunion has been cut short, the Williams sisters remain one of the most successful doubles partnerships in the tournament’s history, having captured six women’s doubles championships together.