When you look at the back of my baseball card, it shows five different big league teams in five years. That total goes up to 14 clubs over six seasons when you add in Minor League stops.

All of my travels made the success I enjoyed this season with the Mariners even more satisfying. I feel like I took the right approach and didn't let the movement affect my performance. My mindset all along was that I'm well-traveled, but I also keep getting picked up, so it demonstrates that there's demand for a guy like me.

After I signed in the summer of 2003, I only spent a few months in the Minor Leagues and started breaking in with the Giants the following year. I always expected to be in the Majors one day; it just came much quicker than I ever thought it would. At that point, I figured if I kept working hard I would be able to make a career of it. But I went up and down because I had trouble finding my niche -- throwing strikes and throwing hard at the same time.

That first trade -- to the Cubs -- was the hardest because I wasn't expecting it. I thought I would be a San Francisco Giant for life. At the time of the trade, I was actually pitching pretty well, but the Giants wanted to improve their bullpen, so they shipped me to Chicago for LaTroy Hawkins.

You learn a lot about Major League baseball the first time you're traded. I understood that LaTroy was a good pitcher and that this game we love to play is a business. I went to the Cubs, which was good and bad. Personally, I didn't want to be traded, but I grew up a Cubs fan so I had that to look forward to. It was kind of cool.

When I got to Chicago, we had a great team. I was really happy with my numbers. Unfortunately, they traded me in the offseason. That was also tough, because I was comfortable with the Cubs, and it was the team that I had rooted for during my childhood. The Cubs had just hired Lou Pinella and were making a lot of positive additions to the team. Now they were sending me to their cross-town rivals -- the White Sox.

My time with the White Sox was a little rocky. I didn't pitch that well, and I don't think I fit with their system, either. It didn't really work out for either side. When the White Sox traded me, it wasn't unexpected or a surprise. In fact, it was the first time a team let me know it was in talks to trade me. There was a lot of waiting and thinking about where I'd end up.

It was awesome when I found out I was going to the Red Sox. I'm thinking that the White Sox didn't want me, but the world champion Red Sox thought I could help their team. It was a great feeling going in there in the spring of 2008 and earning a spot in their bullpen. That was definitely the toughest ordeal I went through as a pitcher -- to earn that spot. They had so many guys competing for so few spots. I beat out two guys who were there before me and who had pitched well the year before. Winning that spot meant so much to me.

Unfortunately, though, I got hurt right before the All-Star break and wasn't right the rest of the season. I just couldn't get healthy and consistent. They weren't sure what they could expect out of me, so I don't blame them for trading me last January. It's part of the business. I was the only guy not under contract or without an option. I had a great time in Boston. I love Boston.

When I got to Seattle, they said the magic words that keep me going: they told me they wanted me. They thought I could have a positive impact and make a difference. I also got an opportunity to close games and continue my development as a pitcher.

I'm more convinced than ever that being positive puts you in position to succeed. I've gone through so many ups and downs in my career that I've learned to keep a positive attitude through it all. I've also seen guys beat themselves up and get down after something goes wrong, and it never helps.

As long as I play, my approach will stay the same: I'm going to have a positive attitude, and I'm going to keep working my tail off to make sure that teams want me.

David Aardsma, still just 27, enjoyed a career-best season in 2009, earning the first 38 saves of his career while posting a 2.52 ERA in a career-high 73 games. He also struck out 80 hitters in 71 1/3 innings.