Clarke joined the western province at the start of the 2013/14 season on a three-year contract but has had to call time on his illustrious career after just one season in Galway.

Having captained the Chiefs to back-to-back Super Rugby titles in 2012 and 2013, Clarke came to Ireland with a big reputation and much was expected of the New Zealander both on and off the pitch.

Best wishes to @ConnachtRugby's Craig Clarke who has sadly had to announce his retirement #Irishrugby http://t.co/AmUGTf2MdJ

— Irish Rugby (@IrishRugby) June 3, 2014

The former Junior All Black played 15 times for Connacht this season, the last of which was against Heineken cup finalists Saracens at Allianz Park in January during which he suffered the latest in a series of head knocks that had dogged the latter stages his career.

In February, it was announced that Clarke was ruled out “indefinitely” as a result of the collision which resulted in his 10th concussion in just 22 months. Acting on medical advice, Clarke has now decided to end his career.

All the best to Craig Clarke on his forced retirement from rugby today @connachtrugby @ConnachtClan @IrishRugby pic.twitter.com/a7RFk0me2i

— Inpho Photography (@Inphosports) June 3, 2014

“While it is of course extremely disappointing the way my career has come to an unexpected end I am, at the same time, so thankful for the opportunities afforded to me through my involvement in the professional game,” Clarke said in a statement.

"Of course I understand that health takes priority over sport every time, but I still can't escape the disappointment that I couldn't contribute to Connacht Rugby as I would have liked and envisaged before my arrival,” he added.

Craig Clarke announces his retirement due to multiple concussions. These multiple concussion horror stories are really, really horrible.

— Whiff of Cordite (@WhiffofCordite) June 3, 2014

Connacht coach Pat Lam paid tribute to the 30-year-old lock both for his impressive performances and the help he afforded other members of the squad.

“Craig could see the potential we have as a young team and he wanted to be a part of that. He was continuously driving standards and challenging areas that needed to be challenged. His consistent, high class performances on the pitch meant he earned massive respect from the outset.

“Even when he was unable to play, he was always helping and mentoring others, encouraging guys from the sidelines in training, staying around to do analysis on other teams and sitting with Dan (McFarland) on the forwards’ play. His work ethic and attitude was inspirational and he had a major influence, leaving a lasting impression on the squad,” said Lam.

Craig Clarke’s full statement:

"While it is of course extremely disappointing the way my career has come to an unexpected end I am, at the same time, so thankful for the opportunities afforded to me through my involvement in the professional game.

"There have been so many people who have helped shape my rugby career and my life and I want to thank them all. My family, especially my wife Veree and my parents Brian and Bev, have been there for me through it all. Everyone involved in my school, club and professional rugby including team-mates, coaches, management staff, medical staff, referees, administrators and volunteers have all helped me along the way.

"I am proud of what I have achieved. I have experienced tough times with teams which has just made me appreciate the good times all the more. While I will always be disappointed not to have worn the black jersey of my country, I will sleep easy knowing that I gave it a real crack, particularly in my last three seasons playing in New Zealand.

"Of course I understand that health takes priority over sport every time, but I still can't escape the disappointment that I couldn't contribute to Connacht Rugby as I would have liked and envisaged before my arrival.

"It was a challenging season in terms of results, but so rewarding in other ways. There are a fantastic group of people here at Connacht and they work extremely hard for everything they have. I really enjoyed getting to know my teammates and working with the coaches. My rugby knowledge benefited hugely, especially around Northern Hemisphere set piece play.

"There will be a lot I'll remember from my time in Ireland. Naturally, our victory over Toulouse was a huge highlight but there are other little things I'll never forget. The Connacht fans are like no other I've ever encountered.

"The first time I ran out through the Clan Stand and on to the pitch, the hairs on the back of my neck stood up. I've never experienced such noise and atmosphere, and from within a relatively small stadium. They are an amazing bunch of supporters and I'd like to thank them for making me feel so welcome here.

"The clapping off of the opposition after a game (except for Toulouse who stormed off straight away after we beat them) is also something that is unique and special to this part of the world. As is the silence of the crowd when kicks at goal take place (with the small exception of Aaron Cruden who had two chances from the side line to win a test match in a very noisy Aviva stadium!). I've really enjoyed my time here.

"Myself and my family will now return to New Zealand and start work on our farm there. I'm also excited about the prospect of getting into coaching at any level and continuing my involvement in the game. I am looking forward to new challenges in life and to spending time with my extended family back home. I will of course be keeping a keen eye on Connacht Rugby and their games next season.

"The birth of our little girl Isabella in Galway means that we will always have a connection with the West of Ireland, and it will be a great excuse to visit again in the not too distant future."