He gets teary and chokes up while talking about the bereavement camps he helped start for children who have lost loved ones.
Then listen to the kids themselves. It's easy to understand why the Philadelphia pitcher becomes so emotional.
Matthew Leist and his younger sister, Tristana, are among the thousands who have benefited from the network of 18 camps around the country set up by Moyer and his wife, Karen.
On July 4, 2003, the Leists lost their mother, Victoria, to cancer.
"After my mom died, I kind of went into a blank mode. Nothing else really mattered anymore," said Matthew, who was 9 at the time. "When I went to Camp Erin and I got a chance to meet other kids who can relate, it was amazing. It's like I was in this darkness and Camp Erin lit everything up."
Matthew, who lives near Seattle, celebrated his 15th birthday Saturday -- the same night the 45-year-old Moyer was set to make his long-awaited debut in the World Series, starting against Tampa Bay in Game 3.
Leist knew exactly what to wish for.
"The Moyers have helped us out so much and they're such nice people that the best present for me would be for him to win that game and have him and his family celebrate," Matthew said.
The camps were named for Erin Metcalf, a teenager the Moyers met through the Make-A-Wish Foundation in 1998 while Jamie played for the Seattle Mariners.
They spent a lot of time with the 15-year-old girl who had developed liver cancer before she died in 2000. Two years later, the first Camp Erin in 2002 in Washington state.
"Erin loved to help other kids," Karen Moyer said. "She's a special, special teenager who lost her life. We wanted to honor her memory."
Children and teens participate in traditional camp activities, meet with grief counselors and interact with peers experiencing similar sorrow at the weekend gatherings.
The Moyers hope to eventually have one in each major league city and plan to expand to 12 new cities in 2009.