By Simon Evans
MASON, Ohio (Reuters) - Former world number one Andy Roddick said a virus was to blame for his recent fitness problems but expects to be back in good shape for the U.S. Open.
Roddick pulled out of this week's Toronto Masters citing an illness and after a lop-sided loss to Frenchman Gilles Simon in the recent Washington Classic third round he complained of feeling lethargic.
The 27-year-old American will compete in next week's Cincinnati Masters after tests showed he had been suffering from mononucleosis, a viral illness.
"I pulled out last week on the advice of doctors. I got some blood work done in Washington, and then again in Texas, and one of them came back positive. I've been dealing with a mild, mild case of mono for the last couple of months that I wasn't really sure about," he told reporters.
"They think I'm fine now. They think I'm most of the way through it, if not all the way through it. It's kind of a mental relief opposed to wondering why and if I was out of shape," he said.
"It's nice to just have a little bit of clarity moving forward. It's not something that's going to affect me, anything super serious.
Roddick, the 2003 U.S. Open champion, won in Brisbane this year and he was playing well until March but he has since slipped outside the top 10 in the world rankings.
The American said he had been feeling out of sorts for the past two months and had been skipping some physical training.
"Normally I enjoy training all day and running all day and doing all that stuff. I opted out of probably four or five workouts this summer that I've never done that before," he said.
(Editing by Ed Osmond)