We perform first-principles electronic structure calculations to explain the anomalous magnetic behavior of the Mn2RuxGa compounds upon Ru doping as shown experimentally recently by Kurt et al. [Phys. Rev. Lett. 112, 027201 (2014)]. Our results suggest that disorder caused by the distribution of the Mn and Ru atoms at various sites reproduces the experimental data. All compounds present antiparallel alignment of the neighboring Mn magnetic moments and, with the exception of Mn2RuGa, none of them presents half metallic behavior. (C) 2014 AIP Publishing LLC.