There is a feeling within some members of the first-team squad that United's injury problems have been caused by an intense pre-season training regime, according to The Guardian. The Red Devils played eight friendlies and took in a 12-day trip to the United States over the summer that left players feeling "overworked". Senior stars have complained about "feeling as tired" at the start of the season as they did at the end of the last campaign. United have been beaten five times already in the Premier League and sit bottom of their Champions League group with one win from four games.