Mariano Rivera’s Unanimous Induction Shows Cooperstown Is Evolving

Twelve people have walked on the moon. What does that have to do with Mariano Rivera?

Even though he pitched in 16 playoffs, that’s one more person than Rivera allowed to score in the postseason.

And while that’s not a statistic that was considered by the Baseball Writers’ Association of America when they were considering Rivera for the Baseball Hall of Fame, the stats the BBWAA did take into account when making him the first player to be voted in unanimously are interesting.

Rivera, who was the first player to appear on the ballots of all 425 writers, was not just a great relief pitcher – the 13-time All-Star is MLB’s all-time saves leader with 652 – but a great pitcher overall and that’s the biggest reason he got more votes than Hall of Famers Nolan Ryan, Greg Maddux, Tom Seaver, and Randy Johnson.

In fact, even though he is a reliever, Rivera’s ERA+ – which adjusts a pitcher’s earned run average for ballpark and run environment – ranks first all-time among all pitchers.

By taking into account advanced stats like that, while ignoring traditional ones like wins (which Rivera wouldn’t have many of as a reliever), the BBWAA is changing the ways they evaluate potential candidates.

“It was probably unthinkable that anyone – let alone a relief pitcher – would be elected unanimously,” according to FiveThirtyEight. “But the Hall of Fame electorate is changing, and that seems to be increasing both the quality and quantity of the players being elected.”