Shahrul who previously played and started his professional football career with Polis Di-Raja Malaysia FA in 2001.
As the 2002 season progressed, Shahrul was part of the team when Perak won the Malaysia Premier League title for two consecutive years in 2002 and 2003.
Shahrulnizam left Perak FA on 17 October 2008 when Kedah head coach Mohd Azraai Khor Abdullah succeeded in obtaining his signature to replace Nelson San Martin to be employed in the box-to-box midfield role, although he can be deployed as a right-sided midfielder.
After a week in the Canaries environment, Kedah FA management had made a decision that Shahrulnizam be handed the number 8 shirt, the number previously worn by Kedah legendary and longest-serving foreign player, Cornelius Huggins.
He was also a part of Malaysia's 2007 AFC Asian Cup squad and get involved in all group stage matches during the competition.