"I learned a lot from watching DJ. I never got to tell him that when he was playing, but I did. The way he handled his business, and how much respect he had for this game, it made me want to be a better player.
"For real, I looked forward to hitting doubles against the Yankees so I could get to second base and say, 'What's up?' to DJ."
Ortiz, 40, wrote that the rivalry between the Yankees and the Red Sox is part of what made playing baseball fun for him.
"Our rivalry with the Yankees made me who I am," he wrote. "The intensity of that competition is what I'm gonna miss the most when I'm done. I could wake up in the morning and my body could be feeling (bad), but as soon as the bus pulls up to Yankee Stadium and I see that white fence on the upper deck, I'm like, 'It's on.'"
While he was growing up in the Dominican Republic, Ortiz said everyone not only wanted to go to New York, but they rooted for the Yankees.
"We looked at New York City like the American dream," he wrote. "The Yankees were like a symbol of everything. If you wore a Yankees hat, maybe your cousin or uncle sent it down to you from New York, and it was like that hat was a symbol of everything you were dreaming to be."
Ortiz said that he was able to bring his mother to New York City while he was playing in the minor leagues in 1997, but she died in a car accident before he became a part of the Red Sox.
"My life has turned out amazing, but the only thing I wish is that she could be here for all this. When I take the field at Yankee Stadium for the last time, she's not gonna be there to see it. That's kind of tough, to be honest with you. But I know she would be so proud that we made it to the top of the world."
And even though he grew up loving New York, he said that's not where he belongs.
"Boston is not just my team. Boston is my city," he wrote. "I consider myself a Bostonian, and it’s the thing I’m most proud of in the world.
"The Red Sox let me be me. You see my beard? The Yankees wouldn’t let me have that beard. I'd be shaving twice a day. But it goes beyond that. The Red Sox let me say what I feel. They let me be myself. If I was a Yankee, I'd be just like my boy, DJ."
Ortiz ended the letter by thanking Yankee fans, but promising that he's bringing his all to his final games at Yankee Stadium.
"When our bus pulls up to Yankee Stadium today, I'm gonna be ready to go," he wrote. "And when I hear you boo me, I'm gonna try to hit the ball over that white fence, all the way to the ... choo choo train.
Ortiz also told The New York Times that over the course of his 20-year career, Yankee Stadium has been one of his favorite places to play.
"Yankee Stadium -- it might be my favorite place to hit, to play, regardless," he said. "The dimensions are perfect for a left-handed power hitter. All the emotions, all the adrenaline, all the competition -- competing against the Yankees has been outstanding."
Ortiz has a lifetime .970 on-base slugging percentage against the Yankees, according to The New York Times.
But despite Ortiz's respect for the Yankees, ending the season doesn't mean getting praise from the team's fans. He wants and expects to be booed.
"When you get used to something and you do well with it, you just don't want to change it," he said. "Basically, I'm so used to them booing me when I step on the field. It feels weird when it doesn't happen."
Read Ortiz's full letter at The Players Tribune and read more at The New York Times.