Godolphin racing manager Simon Crisford says he "deeply regrets" the part he played in hiring Mahmood Al Zarooni.
Al Zarooni has been banned for eight years for administering anabolic steroids to 15 of his Newmarket based horses.
Talking to Channel 4 Racing Simon Crisford said a trainer runs the day-to-day management while a racing manager looks after the best interests of the owner.
He said that he couldn't be aware of every single bit of medication that Godolphin horses were getting.
Racehorse trainer Mahmood Al Zarooni has been disqualified for eight years after 11 of his horses tested positive for anabolic steroids.
The Newmarket Godolphin stables are at the centre of horse doping allegations involving 11 horses and the trainer Mahmood Al Zarooni.