Let sigma be an operator mean in the sense of Kubo-Ando and let del(alpha) a be a weighted arithmetric mean. If Tr(A sigma B) >= Tr(A del B-alpha - max{alpha, 1 - alpha}vertical bar A - B vertical bar) holds for all positive semidefinite matrices A,B, then there exists beta is an element of [0,1] such that sigma = del(beta) .