Jason joined Somerset as an 18 year old bowling all rounder and made his First Class debut for the county in 1993 against the Australians. In 1999 Jason achieved career best bowling figures of 7 for 23 against Leicestershire at Taunton, but in 2001 he moved to Derbyshire.
Sadly a back injury cut his First Class career short and at the end of 2002 he departed from Derbyshire and spent a short while out of the game.
Jason remained involved with cricket and in 2004 he was appointed by Bridgwater Cricket Club as their director of coaching. The following year 2005 Jason returned to Somerset as a self-employed coach and then took up the full time position of Academy Director in February 2006.
During the time he was involved with the Academy a large number of young players went onto sign full time contracts with Somerset including Jos Buttler and Overton twins, Lewis Gregory and Jack leach.
At the end of the 2013 season, Jason was promoted to the role of First XI bowling coach and in October 2017 was appointed as head coach of Somerset, working alongside newly appointed Director of Cricket Andy Hurry.