Sloan, who had spells with Kilmarnock and Queen of the South earlier in his career, had recently turned out on trial for Partick Thistle.
He will join up with former Dalbeattie Star players Kevin Neilson and John MacBeth at Galabank.
Annan have already started their pre-season preparations, following a seventh place finish in their first campaign in Division Three.
Source: BBC Sport
Source: BBC Sport