Former India physio Andrew Leipus on Monday termed the positive doping tests of Pakistan pace duo Shoaib Akhtar and Mohammad Asif as terrible news for cricket.

"It is terrible news for the world cricket. I can't say how it happened, but mostly all doping cases are inadvertent," Leipus told rediff.com.

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Akhtar and Asif have been asked to return to Pakistan following the positive test, conducted by the Pakistan Cricket Board before the team left for the ICC Champions Trophy.

Leipus, who served the Indian team between 1999 to 2005, said, "No sportsperson would be stupid to take banned substances consciously.

"It's not the only the cricketer, but also the physios. They would not do it voluntarily. Nobody would be stupid to destroy anyone's career or their own."

"This generally happens when you take supplements, which are not produced by a reputed brand. They could contain some banned elements, which you may not be aware of," Leipus added.

He said physios are aware of the banned list of substances provided by the World Anti Doping Agency.

"Even when I was with the Indian team, we never took anything on the banned list. Mostly physios are aware of what medicines they give to a player when he is injured," he said.

He said it would be difficult to say how the two Pakistani players tested positive.

"It could be supplements, medication or taking drugs, you never really know. Unless the reports come out, you cannot say anything at all."

He further added that the Indian players always consulted him while taking medicines or supplements when he was in charge.

"We always followed the rules. We tested all our players before going to the 2003 World Cup," Leipus said.