Roger Federer withdraws from Miami Open with stomach flu

MIAMI -- One week after announcing he was going to make an early return to the tennis court, Roger Federer withdrew Friday from his opening match at the Miami Open against Juan Martin del Potro with a stomach virus.

Federer has not played a match since falling to Novak Djokovic in the Australian Open semifinals on Jan. 28. The Swiss star injured his left knee while preparing a bath for his twin daughters the day after the loss. The injury required the first surgery of his career.

"I am very sorry that I have to pull out of the Miami Open with a stomach virus," Federer said in a statement. "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."

The Miami Open was not in Federer's original plans when the season started, but he decided to play after a long layoff.

Lucky loser Horacio Zeballos of Argentina will replace Federer in the draw.

Federer is a two-time champion in Miami but has not won the title since 2006.