The practice court was in a big metal shed out in the middle of nowhere.

It actually used to be an old skating rink, the air outside stained with the faint smell of dog food because of a production plant nearby. It was our second year in Oklahoma City, coming off a 23-59 debut season, one we started 3-29 and had people wondering if we were the worst team of all time.

But this was different. I'd played one season already with Kevin Durant, but he was getting really good. Russell Westbrook was still trying to dunk everything, but he was getting better. James Harden was our new draft pick, and even though he'd just gotten here, he already knew what to do.

There was a new guy named Serge Ibaka that they'd drafted a year before, but he was here earlier than they thought. I wasn't sure if he spoke English, but man, he was a freak athletically.

I remember thinking, "Are we good? I think we're good."

Nobody knew at the time that there were two MVPs -- and a likely future one -- in that gym.

I've played with some incredible players, future Hall of Famers, and had the unique experience of spending my entire career with one franchise, but in two different cities.

I started in cold gyms in small towns in Iowa and ended up playing in more than 1,000 games over 15 years in the best league in the world. I've had an incredible run. I'm proud of my career.

But it's time to go. I'm retiring from competitive basketball.

I spent four years in Lawrence, Kansas, developing habits playing for the Jayhawks that prepared me to play in the NBA. Coach Roy Williams held me accountable: Preseason conditioning, three-hour practices, "gut checks," weights, homework, studying were how I learned to handle my business. And Allen Fieldhouse is incredible -- the absolute best place for basketball in the world.

I didn't know anything about Seattle when I was drafted 12th overall by the SuperSonics in 2003. On the third day of my first training camp, I dislocated my shoulder and needed surgery. I'd have to miss the whole year.

Frank Furtado, a semi-retired trainer with the Sonics, gave me a ride from the hospital that day. On the ride home, he convinced a 22-year-old kid with a lump in his throat that he wasn't going to be a bust. He promised me I would be able to come back from this and have a career. Frank is a legend; he was there for me when I needed someone.

After two shoulder surgeries and many rehab exercises, I was ready to try again the next season. When training camp started I was thrown back in the mix with guys like Reggie Evans, Danny Fortson and Vitaly Potapenko, who all had no problem trying to beat the s--- out of a rookie like me.

"I still remember going to see James at his house the night he was traded. It was a gut punch."

Our coach, Nate McMillan, was old-school. I learned how to take a hard foul and take a lung off with a screen. I learned how to be a pro for 82 games. I struggled at times, but by the end of the year I had a place in the rotation and played well in the playoffs.

KeyArena was loud and the city was with us -- I absolutely loved it. I love Seattle, and I've spent every summer there since I was drafted. I loved being a SuperSonic, and hate how it ended there. I had four coaches in my five years, and then Howard Schultz sold the team to Clay Bennett.

The fans knew we were gone. They stopped coming, and I don't blame them.

Our last season in Seattle we were 20-62, and there was a lawsuit after it to hold the team to its arena lease. But after the mayor took a settlement, we were moving to Oklahoma.

I learned an important lesson: The NBA is a business and all the parties involved will always act in their own best interests. The fans in Seattle deserved better, and I hope they get a team back someday soon.

Nick Collison, right, played four seasons for the Sonics before the franchise moved to Oklahoma City and became the Thunder. Terrence Vaccaro/NBAE/Getty Images

We started in Oklahoma City in 2008 at rock bottom.

Sam Presti had taken the GM job the year before and started trying to build an organization from the ground up. We didn't even have a practice facility when we got there. I remember the first time I even saw Russ play, it was at Southern Nazarene University a few weeks before training camp because we didn't even have a practice facility when we got there.

Then we started 3-29.

Those were some dark days. When coach Scotty Brooks took over, he knew he had to change the spirit of our group. We had some young talent and they knew how to work. Eventually practices became competitive. We were building something. James, Serge and Thabo Sefolosha showed up alongside Kevin and Russ.

We started getting better. We made the playoffs that second season, then Western Conference finals in our third, then the NBA Finals in our fourth.

We made mistakes, but those teams were hungry. I embraced my role -- screened, moved the ball, defended the post and the pick-and-roll. Kevin was showing how good he was going to be. Russell kept growing and started playing with the force other teams have felt all these years.

I loved playing with James and our second unit. It's still crazy to think we had all those guys playing in the NBA Finals under the age of 24. I wish I would have appreciated it more at the time, because things would change fast.

I still remember going to see James at his house the night he was traded. It was a gut punch.

We just sat there together in shock, we couldn't believe it happened. We talked about how it went down, about negotiations and stuff, but we just couldn't believe it.

I mean, we'd just gone to the Finals.

There have been a few other gut punches, but I won't dwell on them here. The eventual 30 for 30 will be really good. It'll probably have to be a four-part mini-series.

Even with all the ups and downs, the players coming and going, the Thunder have been a really good basketball team in OKC for almost a decade, and I've been here for all of it.

When Bennett hired Presti, he was just 29 years old, and together they built an entire organization. They supported us as players and hired people that created an incredible environment for the players to do their jobs. They valued me as a player and a person and looked out for my family. It's rare to have support like that from a front office. I have a ton of respect for them for making the hard decisions and sticking to their plan.

The best years of my career as a player have been in Oklahoma City, and they are the ones who built it.

Nick Collison, left, witnessed the rise of every one of the Thunder's young stars. Layne Murdoch/NBAE/Getty Images

I've been in OKC 10 years now, and the fans have been incredible. They are there every night; they know the game and appreciate effort. From day one we felt the love, and I want everyone to know I've loved playing in Oklahoma City.

It's always meant so much to me and my family that the people of Oklahoma City appreciated what I did. Most people don't get to feel anything like that. I've had it for 10 years and I am grateful.

I love my teammates. My best friends in the world were my first teammates in Iowa Falls. Kirk Hinrich is the toughest guy I played with. Brent Barry has been a mentor to me. Royal Ivey is like a brother to me.

I love KD. I miss him. I played my best basketball with James. I wish we would have had more time. I feel like a proud big brother watching Russ become both the player and the man that he is. I really appreciate all the battles we've been through.

I love Perk [Kendrick Perkins], A-Mo [Anthony Morrow], Dre [Andre Roberson]. Luke Ridnour gave me terrible haircuts, but the way he puts his family above everything has inspired me to be a better father.

Serge and Thabo cleaned up a lot of our mistakes and didn't get enough credit. I learned a lot from D-Fish [Derek Fisher].

Steven Adams is special. He has a unique mix of humility, ability, toughness, and he will do anything for one of his guys. And he has such a sick sense of humor -- I love it. I can't name all the guys I played with here, but I hope all of them knew I wanted to win with them above anything else.

It takes a village to build an NBA career. There are teachers, coaches, different staff members and friends who have all helped me along the way.

Randy Fiscus, my freshman coach was the first one who brought out some toughness in me. I started growing a backbone in those morning practices at Rock Run Elementary School. I appreciate how Billy Donovan handled these last few years of my career. He's always been fair and honest with me. I've learned about being a pro from Mark Bryant every day I walked on the court in OKC.

I would've been done years ago without our medical guys, Donnie Strack and Joe Sharpe, helping me deal with injuries, surgeries, rehab and everything else my body has accumulated over these past 10 years.

I would spend summers with strength coaches Jonas Sahratian at Kansas and Dwight Daub, who would sit in his pickup truck while I would push it in the parking lot. (It was a tiny 1989 Toyota pickup. Probably the smallest pickup you could find, but still.)

Brian Keefe understood my game and what I brought to the team more than any coach I've had. Marc St. Yves, who has been with the organization since he started as a ball boy in 1980, was always available for beers on the road when I needed it (and I'm sure he will continue to be available for beers).

There are so many more special people I've worked with. I hope I showed them my appreciation.

Nick Collison had a front-row seat to the historic play of Russell Westbrook. Mark D. Smith-USA TODAY Sports

I want to say a few things about my family: I really don't know the words to express how I feel about them.

I've had so much support. I've never had to question whether my parents would be there for me. They always will be. They taught me how to take responsibility and how to care for people and not things. They've driven hundreds of thousands of miles to see me play. (There are remains of minivans in junkyards somewhere that can prove it.)

I'm so proud of my 12-year-old daughter, Emma. She's an incredible kid and she's happy her daddy is coming home. My sister and brother have had their stuff overshadowed by my stuff, planned their holidays around my basketball schedule and have always been there.

I have a good woman who loves me. I'm so impressed with her, and I'm looking forward to our future together.

"I feel like a proud big brother watching Russ become both the player and the man that he is. I really appreciate all the battles we've been through."

Playing in the NBA demands a lot and it can be tough on families. I've been co-parenting apart from Emma's mother for eight years. She and I have always been able to put Emma first, and I'm so thankful for that.

Emma's grandparents, aunts and uncles and her nanny have all chipped in at different times to make sure Emma has what she needs and could see her dad enough all these years; I couldn't have kept playing without them.

I'm really blessed, man. I hope I can somehow express how much I appreciate all the people in my life who have contributed to this. I will do my best to try.

I've had the privilege of being one of the guys on a basketball team for a long time. I've loved the friendships and appreciated the camaraderie. There is nothing better than being on the road and going on a run in the fourth quarter to put a game away, then going out with all of the guys after.

I've had a lot of those nights.

I won't get to feel that fire or that rush anymore, but I do get to keep the memories, the stories and the relationships. That's what I will cherish the most. Things worked out for me.

I got to stay here a long time, but now it's time to go.