Among them were Carlos Beltran and Ryan Church, who slammed back-to-back pink-bat home runs for the New York Mets in an 8-2 win over the Cincinnati Reds at Shea Stadium, .
Other symbols at ballparks in Major League Baseball's "Going to Bat Against Breast Cancer" program included pink ribbons, wristbands and shoelaces.
"It's about Mom and it's about breast cancer," Giants catcher Bengie Molina said. "It's everything together. We're playing a game while people are dying and getting sick with cancer. Using the bat is a nice way for us to show our respect and support."
Molina led off the Giants' 4-3 win over the Philadelphia Phillies with a pink bat and singled, eventually coming around to score.
As part of the third annual observation, MLB contributed $50,000 to the Susan G. Komen for the Cure fund.
Pink bats and other symbols are being sold at an MLB auction to raise additional funds.