The Oklahoma City Thunder have said goodbye to a true legend after Nick Collison announced his retirement on Friday after 15 seasons in the NBA.

Collison is the last remaining player on the OKC roster to have been with them since they were the Seattle SuperSonics and has been a part of their rise over the years.

The 37-year-old has been a true fans' favourite in Oklahoma City during this time with the franchise and had a special message of thanks to all the people he encountered in his career.

“My goal was always to make a career out of basketball, and I was blessed to be in the NBA for 15 seasons,” said Collison.

“As my time as a basketball player comes to an end, I’m so grateful for my family, friends, teammates, coaches, fans, my hometown, Kansas University, the Thunder organisation and everyone else who has helped me along the way.

"From the bottom of my heart, thank you. It has been an incredible journey that I’m proud of, and it would not have been possible to do it on my own.”

Collison entered the league in the famous 2003 draft that featured the likes of LeBron James, Dwyane Wade, Carmelo Anthony and Chris Bosh as the Sonics took him with the 12th pick.

In 2008, he moved with the team to OKC and was part of that roster for 10 years. He is one of five NBA players to have spent the past 14 or more seasons all with a single franchise.

“Sometimes, in the early phases of an organisation's life cycle, the right player ‎comes around at the right time to help define their vision,” said Thunder general manager, Sam Presti.

“For the Thunder, Nick Collison was one of those players. Nick has helped define the standards we work by on a day-to-day basis, on and off the court and has become synonymous with the Thunder shield."

Per ESPN, Collison's best season came in 2007-08 where he averaged 9.8 points and 9.4 rebounds per game with 23 double-doubles.

The power forward ranks fourth in Sonics/Thunder history in total rebounds and sixth in blocks.

“I've had a lot of really good people around me,” Collison said. “I've worked hard at it, too, and things have gone my way. I'm very thankful for the career I've had.”

The Iowa Falls native also bid farewell with a video on his Instagram page showing his progression in basketball from his days in college to making it to the NBA Finals in 2012.

Collison may never don an OKC jersey again but he'll always be known as Mr Thunder.

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