First-team opportunities have been limited for Hardinges since he made his debut in 1999.
He made his Norwich Union League debut in 2001 when he scored 65 against Nottinghamshire, sharing a seventh-wicket stand of 164 with Jeremy Snape. Also made 172 in his only innings in 2002.
The former British Universities player is also a useful medium-pace bowler and Gloucestershire have been keen to help develop Hardinges' potential as one of the all-rounders in their squad.
He took 32 wickets in Gloucestershire's 2005 County Championship campaign, but it wasn't enough to stave off relegation into Division Two.
Hardinges enjoyed a solid all-round season in 2006 including a championship century against against Essex.