Disqualified trainer Sam Kavanagh could return as soon as October after the NSW Racing Appeals Tribunal reduced his penalty.

Kavanagh was outed in 2015 for nine years and three months on a raft of charges relating to cobalt in his horses and race day treatments.

Tribunal head David Armati has ruled Kavanagh could not have known the substance described as Vitamin B complex contained cobalt, an illegal substance when above the threshold at the time of 200mcg per litre of urine.

The threshold is now 100mcg/L.

Armati reduced Kavanagh's sentence to four years, five months and one week and it expires on October 26.

Kavanagh will then have to apply to Racing NSW or another state's governing body to regain a licence to train.