Retired U.S. Army Sgt. 1st Class Brian Keaton mimics a grenade toss for the ceremonial first pitch before Game 2 of baseball’s National League Division Series between the Washington Nationals and San Francisco Giants at Nationals Park on Saturday, Oct. 4, 2014, in Washington.

As the 2015 Major League Baseball season gets underway at ballparks around the country, we wanted to spotlight what has become one of baseball’s best traditions: Honoring our nation’s military heroes. This U.S. Army combat veteran’s memorable first pitch during the 2014 MLB playoffs is the perfect photo to set the tone for Opening Day. Play ball!