PRAGUE, Czech Republic -- Czech tennis player Bohdan Ulihrach will appeal against a two-year ban handed him by tennis chiefs after testing positive for the anabolic steroid nandrolone, he said Friday.

Ulihrach, the former Czech No. 1, now ranked 92nd in the world after recent injuries, tested positive during a tournament in Moscow last October.

On Friday he told a news conference that a "B" test confirmed the presence of the banned substance in his body, though he denies ever knowingly taking the drug.

He said he would appeal the mandatory two-year penalty handed down by the ATP.

"My first explanation is that my body produced a little bit more of it ... the second is that I ate or drank something bad in Russia, maybe an energy drink without a proper label," said Ulihrach, who once ranked as high as 22 in the world.

"I always drink what is in a fridge at any tournament."

In proclaiming his innocence, Ulihrach said that tests at the U.S Open at the end of August and another October test in Vienna, a week after the Moscow test, had both been negative.

He said the "B" test showed his level for norandrosterone, a metabolite of the steroid nandrolone, was 3.2 nanograms per milliliter, under the 5.0 maximum accepted level. But the "A" test, however, had been slightly above at 5.2 nanograms.

Ulihrach, 27, said the difference in levels showed there was no premeditated drug use involved in the case. He said the incident would not end his career even if his appeal is rejected.

Czech Petr Korda, the 1998 Australian Open champion and former world number two, was found to have used nandrolone at the 1998 Wimbledon championships and was subsequently banned -- after protracted appeals -- for one year.

Korda, who throughout the ordeal proclaimed his innocence saying he never knowingly took any banned substance, tried a short-lived comeback in December 2000.

Ulihrach turned professional in 1993 and has won three ATP Tour singles titles. He has not played so far this year because of a partially torn calf muscle.

Earlier this year, the ATP announced it would double out of competition testing and increase in-competition testing by about 20 percent to combat drug use.