The Denmark international was two years into a three-year contract and United have sold him to Aalborg for an undisclosed fee.
Sloth was left behind on Sunday as Garry Monk’s squad travelled to Ireland for a two-week training camp, with talks between Leeds and Aalborg at an advanced stage.
He trained under Monk at Thorp Arch last week, the first week of the club’s pre-season campaign, but Leeds concluded negotiations to part company with him yesterday afternoon.