A sport ball may include a casing, an intermediate layer, and a bladder. In manufacturing the sport ball, a panel element of the casing and the bladder may be located in a mold, and a polymer foam material of the intermediate layer may be injected into an area between the bladder and the panel element. In addition, edges of panel element may be heatbonded to each other to join the panel elements and form seams of the casing.