"For me, it's a very significant amount of time," said Moyer this week when asked about the upcoming anniversary. "At the time I was traded to Seattle, the longest I had ever been with one team was about three years. So, did I think that I'd be here for 10 years? No, why would I?"
But why the Mariners? What was it about this organization that brought out the best in Moyer? And after his breakout seasons, what was it about Seattle that made him not want to test free agency?
"I really felt that I found a niche here with this ballclub," explained Moyer. "I had a really good relationship with Danny [Wilson] and the other catchers as well.
"Another reason is that we made some really good friends out of baseball with other parents at our kids' school and things like that. So, it was nice to have our own community of friends here."
And so Moyer stayed and became one of the biggest reasons that the Mariners were able to build from their miracle season in '95 and become one of the elite teams in baseball during the following few years.
That's not how Moyer sees his role with the team though.
"I was just fortunate enough to be at the right place at the right time and to play with a lot of great players." Moyer said. "I feel like we all benefited from each other."
Moyer may not be willing to admit, but the truth is that he was as important a piece to the Seattle's puzzle as any other player during that Mariners era.
In his eight complete seasons with Seattle, Moyer has led the team in wins four times and in ERA four times. He has also led the team in innings pitched six times.
The last stat might be the most impressive because Moyer isn't a kid anymore. He hasn't been a kid for a long time. At 43, he's one of the oldest players in the Majors. And still, he continues to produce.
"I pride myself on my health and contributing to the team I'm on," he said. "To me, those are the most important things. I'm not going to carry a team. I never have and I never will."
And that, right there, is the genius of Moyer. He knows he's not the best pitcher to ever play the game of baseball. Heck, there have been few seasons where he hasn't been the best pitcher in his team's starting rotation. But the fact that Moyer understands this about himself is what allows him to succeed.
That's also what has made him so good for so long. Moyer's style of pitching is not common among Major League pitchers. The idea to pitch soft and softer is not glamorous and it's not encouraged. But it is who Moyer is and so he embraces it.
"My biggest thing is -- just be yourself." Moyer said. "You didn't get here because somebody likes you. You got here because you have the talent to play here. You have to believe in yourself. I'm doing now what I've always done, I'm just more experienced, stronger and around better players.
"Early in my career, I had a lot of ups and downs, but as I've grown and matured, I think that I've figured out who I am and where I fit in and you take that for what it is."
Now the only question becomes: Why keep playing? Why not retire? And Moyer's answer to that complex question is simple. He still does it because he loves it.
"There's still times where I pinch myself because I'm living the dream, I really am, and I'm 43," said Moyer. "So, I'm going to enjoy it as long as I can. I love the competition. I love the challenge. There's time in the offseason and there'll be time when I retire."
When that day does come, Mariners fans can expect a celebration that is saved for only their team's most cherished players. At least it better be special, because Moyer is going to remember it like it just happened.