German great Tommy Haas has been living in the USA for several years now, and in January he thought it was about time he gained U.S. citizenship. Tommy always maintained that he would keep playing for his native Germany. However, I don’t really think Tommy understood that once gaining U.S citizenship that would mean he would have to give away his Germany citizenship. The USA have a policy of not offering dual citizenship’s, its all or nothing.
If you take a look at his ATP Tour player profile you will now notice he plays tennis for the USA.
Haas is out of action until closer to the U.S. Open after having hip surgery, so there has not been any official comment on the reasoning behind this move.