The fly half has scored 358 points for the club and was part of the undefeated National Division One winning side of 2003/04.
"I have spoken to James about the future and we had a long chat about what was going to be involved next season, what would be required of all players at the rugby club," said Ruddock.
"James made it very clear to me that he is thinking about his future outside of rugby. He has a number of business interests and when we talked about the commitment that will be required here we made a mutual decision that the time is right for him to move on.
"Has has been a great player and a fantastic servant for the club. He has helped the club deliver the goods during his time here and I would like to thank him for his efforts. We wish him well in both his business interests and whatever he decides to do next in terms of rugby."