The Dutchman was previously in the same role at Burnley since 2022, working under former manager Vincent Kompany, with whom he previously worked at Anderlecht.
Jelle has also coached for the Dutch Under-20s national team, and at the Eredivisie club where he spent nine years as a goalkeeper, NAC Breda.
He will be straight into action preparing our young goalkeepers Elyh Harrison, Dermot Mee, and Radek Vitek for Monday's pre-season friendly in Trondheim against Rosenborg, which you can watch live on MUTV.
He will then return to Carrington to join Andre Onana, who missed the trip to Norway as he continues to build up to fitness.