Let $M$ be a complete, connected, simply connected and non-invariant extrinsic sphere of dimension $\geq3$ in a locally product Riemannian manifold. If the curvature tensor of the connection induced in the normal bundle satisfies the condition \[ abla_kabla_hR^x_{jiy}-abla+habla_kR^x_{jiy}=0, \] then $M$ is isometric to an ordinary sphere.