Joined Doncaster Rovers in January 1936 having made a name for himself playing in the midland league with Grantham Town. His debut was not long in coming, lining up in the Rovers first team for second division match at Swansea as a centre forward. Rovers were beaten comfortably 2-0 and Bycroft spent the next few weeks in the Rovers reserves where he was ‘reinvented’ as a centre half, making such progress that he was brought back into the team in March and played in all the clubs final 7 games at the heart of the defence and remained a regular from then on.
Syd’s career was interrupted by the start of the Second World War when he was assigned the role of Police officer following the suspension of the Football League schedule, however he continued to play regularly for the club during the war and when the League resumed in 1946 he was once again an integral part of the team.
He missed just 1 match during the clubs record breaking season in winning the third division championship in 1946-47 and over the subsequent years he became the foundation of the Rovers teams, and the team once again won the third division title in 1950 with Bycroft ever present throughout the whole season.
He retired from playing at the end of the 1951-52 season, but having qualified as a coach a few years previously, he stayed on with the club assisting with the coaching and training sessions.
In January 1958, following the shock departure of Peter Doherty, Bycroft and trainer Jack Hodgson were placed in joint charge of team affairs until the end of the season. The pairs first game in charge was be chance, against Peter Doherty’s new team, Bristol City which Rovers won 2-1. The season had not been going well for Rovers who were struggling in Division 2 and despite winning their opening game, Bycroft and Hodgson could only guide the team to one further win all season with the club subsequently relegated. Bycroft and Hodgson went back to their former duties and a new manager was installed, with Bycroft finally leaving the club in 1959 after 23 years with the Rovers.
He made 333 League appearances for the club, scoring twice, but the reality is that had it not been for the war, he would surely have become the clubs record league appearance holder (he made in excess of 150 further appearances for the club in the war time competitions). He had a reputation for being one of the toughest centre halves in the game, he was fierce in the tackle and was a hard, uncompromising man on the field, but a gentleman off it, he will be forever on of the clubs greats.