This week, Mariano Rivera became the first pitcher to appear in 1,000 games with one team. Most people would probably agree that Mariano Rivera is the greatest relief pitcher that ever played the game.But, you can also make an argument that Mo was the greatest pitcher in recent history.
To see how Rivera ranks among all of his pitching peers, we need to come up with a way to statistically compare both relievers and starters. Not an easy task.
Even if we use a newer metric like Wins Above Replacement (WAR) which measures how many wins a player is worth, there is still a strong bias towards starting pitchers. Those guys work a lot more innings and therefore will rake up more WAR, which is a cumulative stat.
Here are the top 10 pitchers of the last 30+ years based on WAR and how Rivera compares to that group…
Rivera is all the way down in the low-60s behind guys like Tim Wakefield (no. 67) and Jon Lieber (no. 68). That doesn’t seem fair. Clearly he is a better pitcher than those guys.
What we need is a rate stat. There is ERA. And Rivera’s 2.22 career ERA certainly ranks among the best ever. But unfortunately, ERA tends to bias towards relief pitchers who often allow runs that are charged to other pitchers.
Instead, let’s scale WAR per 100 innings. That is, on average, how many wins is a pitcher worth for every 100 innings he has pitched? Now we have a stat where we can compare starters and relievers…
And what we see is that, Mariano Rivera has been worth more Wins per 100 innings than any other pitcher over the last 30 years.
What is nice about this stat, is that there does not appear to be a bias towards starters or relievers. The WAR/100 for the top starters and the best reliever are comparable. However, like a lot of rate stats, there is some bias towards younger pitchers like Brandon Webb and Dan Haren. These guys haven’t yet experienced the statistical decline that typically occurs later in a player’s career.
As for Rivera, he hasn’t worked as much as those other guys, but when he does, he has been the most valuable pitcher in recent history.
Not bad for a guy that only has one pitch and has never won a Cy Young Award.