The 36-year old centre-half was released by the Glory recently after 40 A-League matches with the Western Australian club.
With Perth looking towards the future, they have begun to cull their list ahead of next season as finals for this term are now out of reach and Todd, being the age he is, was one that could be let go.
Although he was a consistent performer, the Glory decided to release him and he has since returned to England to link up with former Blackburn teammate Paul Dickov, who is the manager at Boundary Park.
Todd's contract with Oldham runs until the end of the current season. The Latics are currently sitting seventh in England's third tier.