Frank Russo is a baseball collector who doesn’t collect bats, balls, uniforms or autographs.

A 53-year-old resident of East Brunswick, N.J., Russo collects obituaries and death certificates of major league baseball players. He keeps track of their causes of death, and when he can find them, he takes pictures of their gravesites.

And if all of that is not unusual enough, he is a member of the Society for American Baseball Research (SABR for short) who does not consider himself a ...