How much longer can he continue to dominate? It's a telling sign of his greatness that everyone seems shocked whenever he shows any cracks in his armor by giving up a run or blowing a save opportunity, proving that he is human after all. Nevertheless, seeing him play, it is clear that we are witnessing a future Hall of Famer, a living legend, one of the greats of all time.
He is a marvel who rarely shows his age. It is hard to believe he's in his 40s, he still pitches like he's in his prime. His longevity is evident by the number on his uniform -- 42 -- which was retired throughout baseball in honor of Jackie Robinson in 1997. Active players who had the number before the ceremonial retirement were permitted to keep it, and Mariano Rivera is the last one still playing, and playing well.
From the moment he enters a game (especially at home in the new Yankee Stadium to the tune of Metallica's "Enter Sandman"), he brings electricity with him to the mound. He makes it look easy. There are few players (now or in the past) who can measure up to his accomplishments. Soon, he will stand alone.
When the day comes, and it will, that Mariano Rivera will eventually call it quits, he will be impossible to replace. Until then we should enjoy every chance we get to see him play. The memories he's given us are countless, from World Series victories to my favorite moment, when Rivera faced off against controversial homerun leader Barry Bonds in an interleague game, challenging him and striking him out!
Rivera is a class act, a great athlete, and one of the greatest baseball players of all time, and we should all feel lucky to have the chance to see him play in our own lifetime.