Collingwood players Lachlan Keeffe and Josh Thomas have tested positive for the banned drug Clenbuterol, in a sample submitted February 10.

The players have been placed under provisional suspension.

The news comes hot on the heels of the revelation Fremantle tagger Ryan Crowley tested positive for a banned substance last year, while Essendon will find out tomorrow whether their players were guilty of taking a performance-enhancing drug in 2012.

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AFL media boss Patrick Keane tweeted that it was only the players’ A sample that had been tested, while results of the B sample would be known on April 14.

“ASADA has notified AFL that Collingwood players Lachlan Keeffe & Josh Thomas have tested positive for presence of a prohibited substance,” Mr Keane wrote.

“The nature of the substance – Clenbuterol – for the failed test requires the two players to be immediately provisionally suspended.

“The AFL notes that only the A sample has been tested and the players have the right to request an analysis of their B sample.

“The analysis of the B sample is currently scheduled for 14 April 2015. Under the code, players have consented to release of this statement.”

The AFL Players association said they would continue to offer support to the pair.

“The provisional suspension is not an admission of guilt or wrongdoing,” the AFLPA said in a statement. 

Clenbuterol is the same substance that Tour de France champion Alberto Contador tested positive for in 2010.

Contador argued he ingested the drug in a contaminated steak.

The drug can be used alone and in conjunction with other substances to promote muscle growth and reduce body fat.

Keeffe, 24, played 18 games for Collingwood last season, while 23-year-old Thomas played 13.