Roddick, who retired in 2012, and Fish will play doubles together next month at the BB&T Atlanta Open, where Fish is also going to attempt his latest comeback in singles.
Fish has played just one competitive match since August 2013. So he is taking things slowly.
''Unfortunately I can only look to Atlanta, just with how things have gone in the past few years,'' Fish said Monday on a joint conference call with Roddick.
''Still sort of fighting the battle of the anxiety disorder, trying to get a firm grip on how I feel after matches,'' added the 33-year-old Fish, who was born in Minnesota and now lives in California.
The night after Fish lost a match at Key Biscayne, Florida, in March 2012, his heart started racing uncontrollably. A couple of months later, doctors induced extreme palpitations to try to pinpoint the problem. Fish then returned to action at Wimbledon that year.
At the 2012 U.S. Open, Fish won a five-setter in the third round, setting up a match against 17-time major champion Roger Federer. But Fish withdrew before playing Federer.
He remained off the tour until March 2013, when he entered the tournament at Indian Wells, California. He played 10 matches that year, then missed more than 18 months before he returned at Indian Wells again in March.
The Atlanta hard-court tournament begins the U.S. Open Series leading up to the year's last Grand Slam event.
Play begins in Atlanta on July 27. The U.S. Open starts Aug. 31, and Fish would love to be able to be in New York for that.
''Obviously, it's no secret, I'd love to go back to the U.S. Open, where sort of it all came crashing down for me in 2012, and sort of conquer that place,'' said Fish, who reached a career-high ranking of No. 7 in 2011. ''And by 'conquer,' I mean just get back out on the court there. I have a lot of demons from that place.''
He and Roddick, the 2003 U.S. Open champion and former No. 1-ranked player, have known each other for about 20 years.
''With Mardy's comeback, it's been a pretty amazing story. The fact that he's going to pursue that even more this summer is really exciting,'' Roddick said. ''We've been friends for a long time and we kind of just wanted play together one last time, and I wanted to play with my friend and share in his comeback a little bit.''
Roddick said he didn't think they would play doubles together at the U.S. Open because he is expecting the birth of his first child.
This story has been corrected to show that Fish has played once since August 2013.
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