Jean Deysel has announced his retirement from rugby due to injury.
The former Springboks flanker, who joined Ulster from Guinness PRO14 rivals Munster in 2017, made his decision because of a "combination of lower-body injuries and various niggles".
Deysel, who won four caps for South Africa, the last against Australia in 2011, had previously played for Super Rugby franchsies the Sharks and the Lions in his homeland as well as Japanese Top Rugby side Toyota Verblitz.
"Looking back over the last 15 years, there were some highs, some lows, a good couple of laughs, and a few tears as well, but the thing that made the journey worthwhile is the people I met along the way," Deysel said in a statement about his decision posted on the Ulster Rugby website.
"2018 will be the end of my rugby career, but also the start of a new journey off the field.
"I would like to firstly thank the Lord Jesus Christ for blessing me with the ability to play, and then secondly my family and close friends, the Lions and Sharks franchises, teammates and coaches over the past 15 years for their support, encouragement and motivation.
"We really enjoyed our time in Belfast and it will always be our home away from home.
"I want to thank Ulster Rugby for giving me the opportunity to represent this proud Province. I am taking back many memories to cherish and will definitely miss the support and friendliness of the fans since our arrival in Belfast."
Ulster's Operations Director, Bryn Cunningham, said that Deysel was "hugely respected by the players and staff here at Ulster Rugby, but more widely across the rugby world".
"He can rightly be proud of what he's achieved in a memorable career, during which he played at the highest level. Jean's abrasive style of play was great to watch, and he will be remembered as being a warrior on the pitch."