Properties of nuclear matter are calculated in the Dirac-Hartree-Fock approximation within the Zimanyi and Moszkowski model, which considers a derivative coupling in the scalar field. The present model improves the previous sigma-omega version,by the inclusion of the charged mesons pi and rho. The pi N interaction is a mixing of pseudoscalar and pseudovector couplings. The introduction of the pi degrees of freedom has a strong influence on the nucleon effective mass, while keeping the compression modulus in a range of values in agreement with experiments. Effects on the spin-orbit splitting are also discussed.