PRAGUE, Czech Republic(AP) Czech tennis player Ivo Minar has tested positive for a banned substance.

Czech Tennis Association president Ivo Kaderka told the CTK news agency the case is being investigated by the International Tennis Federation.

No other details were immediately available on Monday.

The 63rd-ranked player Minar cited an injury on Friday when he pulled out of the upcoming U.S. Open.

Minar lost in straight sets in Davis Cup singles against Argentina's Juan Martin del Potro on July 10. The Czechs prevailed 3-2 to gain a place in the semifinals.