The five children will be introduced at a news conference Saturday afternoon at Marlins Park, prior to the Marlins facing the Rockies.
Children from across the country have made their submissions of what they're doing to enhance their communities.
"We're looking to get kids active in their community and make their community a better place," Morrison said. "Whether it is starting a recycling program or raising money for a cause for poverty, or whatever it may be."
For weeks, children have e-mailed their submissions and videos to the Project LoMo contest.
The five winners will also take part in the tossing out of the ceremonial first pitches.
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter