Both of Pena's parents were professionals in Santo Domingo. Mery held positions as an accountant and a teacher, while her husband, Felix, was a mechanical engineer. Their positions brought a comfortable life to the family of six in the Dominican Republic.
But somewhere along the way, living the American dream crept into Mery and Felix's conversations.
"My mom was an established professional in the Dominican Republic," Carlos said, "and when the opportunity came to come over to the United States, they had a decision to make because they had to think about, 'Do I leave my stable life, my friends and my social life? My professional life? We're doing well.' Does she leave that for what they thought could be a better future for us here in the United States, with more opportunities?"
In 1992, the couple loaded up the family and moved to Haverhill, Mass., where they lived in a small apartment. Each parent had to accept a job far below what each of their experiences and educations merited.
"I've always been very appreciative of the fact that they put themselves second," Carlos said. "Because they understood they would have to start over -- all the schooling that they had done, the hard work that they had to set forth before they were able to achieve their professional status. I was fortunate enough to have some parents who were really able to provide for us.
"So for them to say, 'I'm going to put that behind. I'm thinking more about my kids. I want them to learn a second language. I want them to expand their horizons.' But they knew their decision was going to affect them. And all of a sudden, their degrees would have to be validated again. I can only imagine them sitting there and talking about, 'What are we going to do?'"
In Massachusetts, Mery worked at a nursing home and did housekeeping. And though the job wasn't what she had been trained to do, she managed to find joy.
"And she did it so gracefully and respectfully -- she worked really hard," Carlos said. "That's what I love about her. She did it with so much love, even though you could say she was a little more comfortable in the Dominican Republic. This kind of work was more physical, let's put it that way. She was well into her late 40s at this time. I was 14, and I never heard her complain. She gracefully adapted."
The Rays' first baseman smiled when asked if he got his easygoing disposition from his mother.
"I have a lot of her in me -- a lot," Carlos said. "People say that often. She sees the best in people. She's very calm, always happy and she's very laid back. She gets along well with everybody. She's very easy to like, a very special woman."
Now that Mery has raised her family, she has transitioned into the role of grandmother for Carlos' children, Isabella and Nicholas.
"She's a great grandma," Carlos said. "She has that teaching thing. When she's with her grandchildren, I always see her trying to teach them, showing them letters and all kinds of things. 'Grandma Mery,' that's what we call her."
Carlos noted that his mother is "monumental in my mind."
"She deserves a monument, in my opinion, when I see what she has meant to me," Carlos said. "I have been blessed with an unbelievable mother. To this day, all I can say is thank you, thank you, thank you. To this day, I cannot express how grateful I am -- for everything she has done for me and all the love she has given me."
Carlos would not divulge what he planned to do for Mery on Mother's Day.
"I try to surprise her every year with something," Carlos said. "We'll see what we come up with. I'm pretty creative."
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.