Top-ranked U.S. tennis player Mardy Fish says he's "not 100 percent sure" when he will return to the tour after a health scare this month.

Fish hopes he can play in the French Open, which begins May 27. But he says he might wind up having to miss the year's second Grand Slam tournament.

Fish also says doctors are still doing tests to try to figure out exactly what forced him to pull out of the U.S. Davis Cup team's quarterfinal against France in early April.

In a telephone interview Tuesday, the No. 9-ranked Fish says he's "doing OK" physically and "taking some time now to kind of relax and try to keep my mind off tennis a little bit."