The former Norwich midfielder (pictured right playing for the Canaries) has a wealth of experience, including a successful role in the newly promoted Wigan Athletic side during the 2005.
Jarrett will arrive at a crucial stage in the season for Rob Kelly, especially after the departure of fans favourite Gareth Williams after the star was snapped up by struggling Watford in the January transfer market.
A delighted Rob Kelly said: 'He's a player I know quite a lot about. He's been promoted out of this division and knows what it takes to be successful in the Championship. He's the type of modern midfield player that we need.'
The new signing has been given the number 23 shirt and is expected to replace injured Stephen Hughes in Saturdays away trip to Ipswich Town.