Editor's note: Alex Rodriguez has a unique relationship with the four players voted into the 2019 Hall of Fame class. He was teammates with three of them (Mariano Rivera, Edgar Martinez and Mike Mussina) and played against Roy Halladay throughout their careers. In the days leading up to their enshrinement in Cooperstown, A-Rod shares the stories of those stars -- as teammates, competitors and friends -- in his own words.
Mariano Rivera will be inducted into the Hall of Fame on Sunday, the greatest relief pitcher ever, the first unanimous selection. What fans will always remember about him was how unflappable he was on the mound, how stoic, in victory or in those rare moments of defeat.