Roberts arrival at United was extremely important to the development of the club; a strong, skilful, fast centre half and a rebel to boot.

He flouted FA rules by wearing his shorts above the knee[4] and was politically minded in favour of the unionisation of professional footballers.

[5] He left the club in August 1913 for a then record fee of £1,500 to Oldham Athletic, who he also went on to manage, after appearing in 299 matches and scoring 23 goals for United.

In August 1909, the FA threatened to suspend any player who admitted to being a member of the Union, following which Roberts and his Manchester United's teammates were summoned to a meeting with the club's management.

The players refused to relinquish their Union membership, forcing the club to contact their first opponents of the new season, Bradford City to cancel the fixture, as it could not field a team.