Channel Seven reported on Friday night that the pair had been told their B samples had confirmed they had ingested the banned substance, clenbuterol.

The Magpies told Fairfax Media they were unaware of the results of the test. The positive B sample will now mean the pair receive an infraction notice, appear before the AFL's anti-doping tribunal and potentially face a two-year suspension.

Keeffe and Thomas tested positive to the banned substance in February and have been under provisional suspension since they received notification on the eve of the home and away season. They have effectively been exiled from the club since that point.