A sport ball may include a casing and a bladder located within the casing. The casing may include a plurality of panel elements joined to each other with welds, and portions of the panel elements that include the welds may project toward an interior of the ball. A method of manufacturing a sport ball may include providing a plurality of casing elements that include a thermoplastic polymer material. Edges of the casing elements are welded to each other to join the casing elements. The casing elements may then be turned inside-out through an aperture formed by at least one of the casing elements, and the aperture may be sealed.