Heat oven to 325°F. On rack in shallow roasting pan, place pork. In small bowl, mix marmalade, orange juice, fennel, thyme and sage. Brush half of the marmalade mixture over pork.
In large bowl, toss sweet potatoes and Brussels sprouts with oil, salt and pepper. Arrange vegetables around pork. Insert ovenproof meat thermometer so tip is in thickest part of pork.
Roast uncovered 1 hour. Brush pork with remaining marmalade mixture; gently stir vegetables to coat with pan juices. Roast about 15 minutes longer or until thermometer reads 155°F and vegetables are tender. Cover pork with foil and let stand 10 to 15 minutes until thermometer reads 160°F.