Roger Federer only missed a few months due to surgery for a torn meniscus in his knee and was set to make his return at the Miami Open. However, he came down with a stomach illness that has forced him to withdraw from the tournament the same day he was supposed to play Juan Martin del Potro.

The last match the 17-time Grand Slam champ played in was an Australian Open semifinal loss to Novak Djokovic in late January. He also admitted the Miami Open was not on his schedule initially, but noted that his plans changed during his knee rehabilitation.

"I am very sorry that I have to pull out of the Miami Open with a stomach virus," Federer said. "I feel bad for the tournament and the fans as I have rarely ever had to withdraw at such short notice. I have not felt great for a few days, and, unfortunately, it got worse in the last 24 hours. I was really excited to have my comeback in Miami, but I am in no condition to play. I tried to warm up this morning, but it was clear that I could not compete."

A pillar of health throughout his career, the 34-year-old Swiss tennis star injured his knee while bathing his twin daughters. Despite getting major surgery for the first time in his career, Federer was only sidelined for about two months.

"It happened the day after the Djokovic match," Federer said at a press conference Thursday. "I woke up. I don't know exactly what happened. I think I was going to run a bath for the girls.... Very simple movement, probably a movement I've done a million times in my life for sure."

Federer continued: "When I got the news that I had to have the operation, I saw the pictures and talked to my doctor and knew that it was the only way out of this one. In the hospital, when I was about to go into the operating room, that's when I got nervous and sad about it all.

"When I woke up and looked at my knee it was like, 'This doesn't feel like my leg. I can't believe I did the operation and I hope it will come back from here,'" he added. "That's when I got scared. Then, literally, one day, two days later I had no more pain."

Rafael Nadal acknowledged the men's tennis game is better when his old rival is active, and said he was glad Federer did not have to withdraw because of his knee.

"It's obvious that a tournament with Roger is always better," he said. "It's good that it's a stomach problem and, at the same time, it is not the knee, so it's not a big deal. But it's obvious that it's terrible news for the tournament."