Collingwood duo Lachie Keeffe and Josh Thomas have been banned from Australian sport for two years and delisted after accepting doping bans from ASADA.

On Monday, the pair admitted to using illicit drugs in February this year, which they believe were laced with Clenbuterol, a steroid on the WADA prohibited list.

Keeffe, 25, and Thomas, 23, announced they would not challenge the ASADA charge tabled against them for a positive test.

They will serve two-year bans, backdated to start in March 2015, and have accordingly been delisted.

Under ASADA and AFL guidelines, they have also been fined around $50,000 each but Collingwood has thrown them a career lifeline by committing to re-drafting the pair as rookies should they nominate.

Thomas insisted he and Keeffe never set out to illegally dope.

“We can only assume it occurred in a night out prior to testing, on which we took illicit drugs,” he said.

“Although we can’t be sure, we believe the substance we took was laced with Clenbuterol.

“We want to stress that at no stage did we knowingly take Clenbuterol.”

Keeffe said he had struggled to cope at times since receiving the first notice of a positive test in March, but understood and accepted the outcome.

“We take full responsibility for our mistakes and we accept the consequences,” he said.

“We hope others will learn from our mistakes.”

Collingwood chief executive Gary Pert said they would regret the decision for the rest of their lives.

“Their decisions will cost them two years of playing AFL football, the game they’ve loved and have dreamed of playing every since they were playing,” he said.

“It will ultimately cost them hundreds of thousands of dollars and dented their reputations.

“After a two-year break there are certainly no guarantees they will play AFL football again though I must admit I hope they do.”

Magpies football manager Neil Balme said the club’s decision to commit to re-drafting Thomas and Keeffe as rookies was in part to provide them with hope.

“We’re keen to given them the light at the end of the tunnel … if they want it,” he said.

Keeffe gave an undertaking he would be putting his name forward for the rookie draft at the end of 2015.

“We hope that an error of judgment does not become a life sentence,” he said.

“Having worked so hard to build AFL careers, we are now committed to starting again and we hope to regain everyone’s faith and trust and return to the AFL in 2017.”