Mean Joe Greene was watching the Pittsburgh Steelers play the Minnesota Vikings on Sunday when he got a call from Mel Blount, one Hall of Famer to another. Their old teammate L.C. Greenwood had just died from kidney failure two weeks after back surgery.

Greene went silent. Images flashed through his mind: Three months ago, seeing L.C., so jovial in his Santa Claus hat at Franco Harris's 40th anniversary celebration of the Immaculate Reception. Then, talking with L.C. by phone, just before his surgery, his old teammate describing...