The 29-year-old South African born tight head prop has been a force in the Scarlets front row since 2009, and has played 52 games for the Scarlets with 17 appearances this season and four tries on the score sheet in 2011/12. His first competitive game for the Scarlets was against Leinster, his final game in the shirt on the 7th of January against Glasgow.
He joined the west Wales region from the Newport Gwent Dragons where he played for Newport RFC and the Dragons from 2003 to 2009. Thomas has seven Wales caps - his first against Argentina in June 2006 and he was part of the Grand Slam triumph of 2008.
Thomas suffered a heart attack in early January while on training duty at Parc y Scarlets. His life was saved by the swift actions of the Scarlets medical team, the rapid response of the ambulance service and staff at Swansea's Morriston Hospital where he underwent bypass surgery.
Rhys Thomas said: "At the moment, it is about spending time with my family and friends and I'd like to thank my wife, Paula, for all her support. I'm just concentrating on getting myself fit and healthy again and that could take 12 months after what's happened.
"The support I've been shown has been incredible and I'd like to thank all the Scarlets rugby supporters, my colleagues at Parc y Scarlets, fellow players, people across the rugby world and all those who have send me their best wishes. To receive so messages over the past few months has been a real boost to me and my family during a fairly challenging time."
Father of four Thomas, said he was looking forward to spending more time with his children Ashleigh, 17, Ethan, 13, Morgan, six and Kai, four.
Rhys says the ending of his playing career has been very difficult to come to terms with but the experience of nearly losing his life has given him a new perspective on the future.
He said: "It is a tough thing to take and to come to terms with. The intensity and commitment that's required at the top end of professional rugby means it becomes a huge part your life; and to have that suddenly stripped from you, takes some getting used to.
"I've only ever played rugby and that's all I'd ever wanted to do and to be told that's it's over so suddenly has been hard to get my head around. But I am grateful to the Scarlets and our supporters who have been really supportive and given me all the backing I needed."
Thomas said he is now on a special diet and fitness regime to build back his health. He added that he'd like to stay in rugby as it's all he has ever known: "It's still early but I know that I want to stay in the game that means so much to me. Perhaps coaching, helping out young front rowers. There's a number of things I might be able to do.
"I've thoroughly enjoyed my career at the Scarlets and the boys are a great group to be part of. The spirit of this team and the development of players at Parc y Scarlets is something pretty unique. It's been tough to close this chapter because I really felt I was hitting some form this season. But I have to move on now and I'd like to take this opportunity to thank everyone at the Scarlets."
Scarlets Head Coach Nigel Davies said: "We were all very shocked by what happened to Rhys, this is a very tight group of players and a close-knit environment so anything that impacts on individual players affects us all.
"It has been good to see him so well now and happy and we will continue to support him in any way we can and wish him the very best in the future for a healthy and happy life with his young family.
"Rhys has always shown a ferocious amount of bravery and guts on the pitch and in the next chapter of his life, he will no doubt do the same and succeed in whatever he chooses to do. Our thanks to him as a Scarlets player, he has brought great physicality and intensity into forwards play and his contribution has been significant. He has dealt with this whole episode with bravery and composure and he has all our respect as a group for that.
"Rhys and Iestyn are both tough acts to follow in the front row but we'll take our time to ensure we make the right choices in the future and we have some bright young players coming through our system too.
"We are now in the middle of recruitment to bolster our front five for next season and that is a very detailed process in terms of profiling players and analytically studying how they fit together within our squad. We need to get the right players for our environment. The important thing is that we take our time, find the right solutions and that we are analytical in our approach not reactive. We are encouraged by a number of options open to us in recruitment."