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A. It is well-known for self-adjoint scalar Jacobi operators that their absolute continuity and the absolute continuous spectrum in a subset of the real line can be characterized by non-existence of subordinate generalized eigenvectors. In our work we explore to what extent a similar relation is true for block Jacobi operators. In this setup, under some uniformity conditions, we show that nonsubordinacy in the sense of matrix generalized eigenvectors also implies the absolute continuity, similarly as in the case of the scalar Jacobi operator. Namely, we get the absolute continuity of the matrix spectral measure with the invertibility of its density almost everywhere. We also present an example showing that the reverse implication in general does not hold. We extend some sufficient conditions for nonsubordinacy from the scalar to the block case. Finally, we give applications of our results to some classes of block Jacobi matrices.