Chesterfield's unbeaten run in August, comprising of four wins and a draw, resulted in Cook being chosen. Alan Curbishley, who heads the Sky Bet Manager of the Month judging panel, said: "Chesterfield have made a solid start to their campaign. Paul Cook's team are top of the league and have shown early consistency."
Roberts' impressive start to the season included three goals in August. Sky Bet Head of Football Paul Wiggins said: "This particular signing caused a stir in the Sky Bet offices in June and so far Gary Roberts is living up to expectations. A player who stood out at times for Swindon and Huddersfield in League 1 was always likely to have a massive impact in League 2, and this has been the case so far."
Sky Bet Football League pundit Don Goodman added: "Technically gifted and with an eye for goal, Roberts has shown Chesterfield fans just why they're lucky to have a player like him in their team."