Andrew Harris has taken steps to try to prove his failed drug test was unintentional.

The Winnipeg Blue Bombers star running back was practising with the team Tuesday after serving a two-game suspension for testing positive for an anabolic steroid called metandienone.

When he was suspended, he said the source was a contaminated over-the-counter natural supplement he took and he planned to send the leftover product away to be tested.

"It's been shipped away and I'm just waiting to hear back," Harris said after practice. "Again, it's like a needle in a

haystack, but I'm doing everything I can to get some answers."

The 32-year-old Winnipeg native still leads the league in rushing with 908 yards off 141 carries through 10 games.

The Bombers (9-3) travel to play Montreal (6-5) on Saturday and went 1-1 without Harris.