He is a right-handed batsman, a wicketkeeper and an occasional right-arm offbreak bowler. As a youth he toured New Zealand with England Young Cricketers in the 1990-1991 season, playing two test matches and two one day internationals. He made his first team debut for his home-town team Northamptonshire in 1992, and played for the county in 109 first class matches over ten seasons.
During this time he made ten centuries, with a highest score of 201 not out, but only reached the landmark of 1000 runs in a season once.
In 2001. Warren left Northamptonshire at the end of the 2002 season. His departure was occasioned by a dressing room split after he began going out with the ex-fiancee of his fellow wicketkeeper Toby Bailey.
Following this, Warren played for Nottinghamshire in the 2003-2006 seasons. Despite scoring five first-class centuries in this period, he was released at the end of the 2006 season.