Aleksandar Donev,1,2 Salvatore Torquato,1,2,3 Frank H. Stillinger,3 and Robert Connelly4 1Program in Applied and Computational Mathematics, Princeton University, Princeton, New Jersey 08544, USA 2Materials Institute, Princeton University, Princeton, New Jersey 08544, USA 3Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA 4Department of Mathematics, Cornell University, Ithaca, New York 14853, USA (Received 31 January 2004; published 25 October 2004. Phys. Rev. E 70, 043301 (2004)) Abstract O'Hern, Silbert, Liu, and Nagel [Phys. Rev. E. 68, 011306 (2003)] claim that a special point J of a "jamming phase diagram" (in density, temperature, stress space) is related to random close packing of hard spheres and that it represents, for their suggested definitions of jammed and random, the recently introduced maximally random jammed state. We point out several difficulties with their definitions and question some of their claims. Furthermore, we discuss the connections between their algorithm and other hard-sphere packing algorithms in the literature.