Collingwood sought assurances from ASADA that more of their players had not failed drug tests after two of their players were found to have both tested positive to the same banned drug on the same day.

Lachie Keeffe and Josh Thomas both tested positive to the performance-enhancing drug clenbuterol on February 10 this year. The club's last full day of their training camp in New Zealand was on February 7.

The club and the players learnt of the positive test – the A sample – on Friday. The pair was stunned to be told of the positive test and strongly protested their innocence, club football director Neil Balme said.

"We are hoping there is a good outcome but we are accepting at the moment they are not going to be available and it could be for some time," Balme said, adding that the players were stunned.

"It was disbelief from both of them. They both said: 'We haven't done this,'" he said.

Both players face the sack if convicted as they face what is understood to be a four-year ban and both players are out of contract at the end of the year.

The players had no immediate explanation for how the drug came to be in their system. There has been speculation of contamination in meats, or in other substances the two players may have taken.

The club also had no explanation for the coincidence of two of their players testing positive to the same drug at the same time.

"The first question I asked ASADA is, when we went through the fact there was two players, is there any more? That is the obvious question to ask and they said no," Pert said. "So I can only go off what they told us in that conversation."

Collingwood's integrity officer conducted an audit of the club's dietary and nutrition program and was satisfied the systems were clean.

Clenbuterol is a banned substance under the WADA code. The players are awaiting the results of a B sample, which will not be known for several weeks.

Pert said the players had separate legal representation and the club had only had limited discussions with them to explore the possibilities for how the drug came to be in their systems.

Pert said he was "devastated" to be called by ASADA on Friday with the news and in particular the identities of the two players "because we're talking about two of the highest-quality men".

Keeffe was in Collingwood's leadership group last year while Thomas is also known to be one of the strictest players on how he trains and prepares. The players, both Queenslanders, are good friends and previously lived together.

The club was keen for the identities of the players not to remain anonymous because they wanted to be transparent and felt it would also have been unfair for other players to be speculated about.

"When we spoke to the players and asked can you see any reason for this test, they both said no," Pert said. "These are two men who are in shock, who were at home on Friday and had ASADA knock on their door. Both Neil and myself spoke to them shortly after and the only way I can describe it is quite shell-shocked so, no, we were not pressing for all the questions you might think as we calmly sit here that we might be asking."

Pert said the club wanted to support the players and a decision would be made next week on  whether it was appropriate for the players – who are immediately provisionally suspended – to remain training with the playing group.

Balme said the club was well aware of what clenbuterol was and that  made it even more difficult to comprehend those players taking it.

"We know what it is. That is one of the reasons why we think 'why would they?' They would have to be actively pursuing it and wanting it.

"If you look at both of these players, it doesn't make any sense for either of them to use this because they are both quite lean ... they don't need it, they are very fit, it doesn't make any sense," he said.

Coach Nathan Buckley broke the news to the full playing group on Monday morning, as they prepared for the season opener against

the Brisbane Lions on Saturday.

Pert said  regardless of the eventual outcome there was significant damage to the brand of the club.

"We have had a very short conversation.

"We have been given no plausible reason why it has happened and now the players with their representatives have got to decide how this rolls out from their perspective as well," Pert said.