By Ryan Cooper, CNN
(Jupiter, Florida and Scottsdale, Arizona) - A growing number of Major League Baseball players are coming together to make every pitch, home run and strikeout count in the fight against child trafficking.
The players are pledging to donate money for each of their on-field achievements this season to the Free 2 Play campaign, a platform for the California-based Not For Sale non-profit group.
"A lot of Americans are shocked to hear that there are 30 million people living in slavery today, and [many] of those are children," Dave Batstone, Not For Sale's co-founder, said. "So we decided to create a program that not just releases a child from slavery, but provides them a new future."
Jeremy Affeldt, a relief pitcher for the San Francisco Giants, has been one of the most vocal athletes raising money and awareness for Not For Sale. Last season, he pledged $250 for every strikeout he pitched.
Affeldt has been recruiting teammates and other teams' ball players to join the fight.
"This is an opportunity for us as ball players to join together as one team, to support something that's very, very important," Affeldt said.
This season, at least 17 players from MLB have signed up to Team Free 2 Play, with more expected to join the effort.
Josh Collmenter, a pitcher for the Arizona Diamondbacks, said he wanted to take part after hearing Affeldt and Batstone speak about the global problem of modern-day slavery.
"It is definitely something I wanted to make sure I did to give back to the community and be a role model and help out where I can," he said.
But it's not just players who can make a difference. Fans can now get involved, too.
This season, Not for Sale has launched a new Free 2 Play Facebook app. It allows fans to pick their favorite player and stat, and then pledge a donation for every on-field achievement.
For example, fans of St. Louis Cardinals player Matt Holliday may choose to pledge 25 cents for every home run he hits this season.
"A fan can choose their favorite team, their favorite player, their favorite stat – and pledge 50 cents, a dime, doesn't matter what the money is – but they can participate," Batstone said.
Every little bit counts, organizers say.
"When it comes to raising money, it's not about going after big hitters, it's about going after a large amount of people who give a little," Affeldt said. "And you can do a lot of damage with that."
To take part in Free 2 Play, you can log on to Facebook and search for 'Not For Sale.' Then click on the Free 2 Play app.