If sports talk shows are to be believed, Mondays are brutal for professional and college football players. Particularly those who play for teams that lost the Saturday or Sunday before.
Monday is the day in which film of the previous game is closely studied, and errors showcased. In sports there's no sugarcoating or coddling. Errors are realized right away, often in humiliating fashion, and corrected. Those that don't correct their mistakes are quickly benched, or released.