Barnes, who is active in raising money to fight childhood cancer, said fighting breast cancer was personal for his family.
"Breast cancer is big in my family -- my wife's mom passed away from it," Barnes said. "It's another charity that we want to do stuff for. We do the run, the Race for the Cure, in California every year. Any cause like that we look forward to doing something with it."
Barnes said he used pink equipment every year he played in the Minors.
As was the case throughout baseball Sunday, there was a little bit of pink all over the field as the Rockies took on the Reds. Shortstop Troy Tulowitzki, third baseman Nolan Arenado and first baseman Justin Morneau wore pink shoes, as did outfielders Carlos Gonzalez and Charlie Blackmon. Pink sleeves and shoelaces and neck bands were the norm.
Thomas Harding is a reporter for MLB.com. Follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.