He started playing football at the age of six with Excelsior Rotterdam. He ran through all youth teams of this club. Bruins made his professional debut for Excelsior in the season 2004–05. On January 28, 2005, Bruins came in for Santi Kolk in the 78th minute of the Eerste Divisie away match against FC Eindhoven (3-0). This was the only match in his first season. The next season he had his breakthrough. Bruins scored his first professional goal in the season opening away match against Cambuur Leeuwarden (0-1) on August 12, 2005. With Excelsior he became champion in the Dutch Eerste Divisie in the 2005/06 season.