A spherical sport ball may include a casing that includes first and second substantially hemispherical panel components. Each substantially hemispherical panel component may be a unitary structure having a central panel and a plurality of polygonal peripheral panels adjacent to the central panel. In addition, the first substantially hemispherical panel component may be joined with the second substantially hemispherical panel component at a non-linear, circumferential seam between peripheral panels of the first hemispherical panel component and peripheral panels of the second hemispherical panel component.