I heard a stat the other day and it blew my mind:

In human history, more people have walked on the moon than have scored an earned run off of Mariano Rivera in the postseason.

Sounds crazy, right? But it’s true.

According to NASA, 12 people have had the privilege of walking on the moon.

According to Baseball Reference, 11 people have scored an earned run off of Playoff Mo.

And while no statistic could ever truly encapsulate Mariano, I figure this one is as close as we’re going to get. Because I think it really gives you a sense of what sort of greatness we’re dealing with, when it comes to Mo. It’s hard to compare him to other closers — in fact, it’s hard to compare him to other pitchers.

Mariano is just on another level.

Howard Earl Simmons/NY Daily News Archive/Getty Images

The thing I respect most about Mo is that what you see is what you get.

A lot of people I’ve met over the years, they’ve asked me what Mariano Rivera is like off the field. And I’ll tell you what I tell them — which is that he’s pretty much the same person you watched for all those years on the mound.

There’s no “persona” with Mariano. He’s never had a character that he portrayed. He’s always just calmly and coolly done his thing. He’s quiet. Thoughtful. Intense. He’s a man of faith.

He has an incredible eye for detail.

Have you ever seen a Mariano Rivera autograph? Google it when you get a chance. With a lot of guys, their signatures are these quick little scribbles. But Mariano, man, if he’s signing something for you, he takes his time. He puts care into it, until he gets it just right — like with everything else he does. To me, right there … that’s Mo.

And like I said: It was always the same thing on the mound. There wasn’t much mystery if you were facing Mariano Rivera. No smoke and mirrors — nothing to hide. The scouting report was the same every time. Mo knew he was going to throw that cutter. The guy at the plate knew he was going to throw that cutter. Fifty thousand plus at Yankee Stadium knew he was going to throw that cutter.

And it wouldn’t matter.

Because Mo wasn’t trying to trick you.

And in the end, like it or not, he was just going to flat-out beat you.

Elise Amendola/AP Images

During my first full season in the minors, when I was 18—19 years old, Mariano was coming back after having had surgery on his arm. So one of the things I’d do from shortstop was keep track of Mo’s pitch count.

And although eventually I stopped counting his pitches, it’s funny — in a way, I never stopped being that 18-year-old kid. Because for all of the amazing things that happened to me over those next 20 years with the Yankees, I never stopped being aware of this one: that on any given night…. if we could just get ourselves a lead….

I had the best seat in the house to watch the greatest closer of all time.

Hall of Fame teammate. Hall of Fame person.

And now, officially, a Hall of Fame player.

Congratulations, Mariano, and the rest of this year’s class.

—Derek