The statement from Ulster Branch read,
Justin has received a financial offer that he feels at his stage of his career and with a young family, he must accept for his long-term financial security.
Ulster Branch Chief Executive Michael Reid, commented, "We are sorry to lose Justin, but understand his decision. Justin has contributed a huge amount to Ulster Rugby, both on and off the field and I wish him well."
Fitzpatrick, won the last of his 23 caps when he came on as a replacement in the game against England in Lansdowne Road on Sunday last, having made his international debut against South Africa on the 1998 summer tour. He moved from London Irish that year and has been an integral part of their squad since, playing a crucial role in his side's European Cup victory in 1999.