The Real Best Reliever in Baseball

The best relief pitcher in baseball is not who you think he is. Most of you probably would not even include him in the top 10. If I were to take a poll on who is the best relief pitcher in baseball, the top voted would likely be Zach Britton, Dellin Betances, Aroldis Chapman, Kenley Jansen, and Andrew Miller. I will say that it is none of them. To illustrate my point, I will compare this mystery pitcher’s numbers to all of their numbers. Nothing too scary, just xFIP, K/9, and ERA. I also will not just tell you which pitcher produced which numbers. Where would be the fun in that? I will compare the numbers of all six pitchers and walk you, the reader, through determining which one is the best.

Pitcher A: 1.18 xFIP; 14.89 K/9; 1.45 ERA
Pitcher B: 1.92; 13.97; 1.55
Pitcher C: 1.17; 16.84; 1.16
Pitcher D: 1.75; 15.53; 3.08
Pitcher E: 2.41; 13.63; 1.83
Pitcher F: 2.09; 9.94; 0.54

At first glance, Pitcher F’s ERA of 0.54 is likely what stands out most. Alas, even calling him only by a letter cannot mask Britton. He has the lowest K/9 by far and the second-highest xFIP, so Britton is effectively taken out of consideration.

Pitcher D has an ERA over a run higher than any of the others. His K/9 and xFIP fit in the range but do not stand out. Thus, Dellin Betances is out as well.

Of the remaining four, Pitcher E rates the worst in each of the three categories. Goodbye, Kenley Jansen.

That leaves us with Pitcher A, Pitcher B, and Pitcher C. In this group, B is the worst across the board. Aroldis Chapman leaves the conversation.

Pitcher C is better than Pitcher A in all three statistics. Andrew Miller bows and exits.

Carter Capps stands victorious.

Yes, I know Capps did not pitch in 2016. I used his 2015 numbers. They stack up just as well against the elite relievers from that year as well. It is true that Capps pitched only 31 innings in 2015, but the stats I used are rates. Maybe a larger sample would have dragged him into mediocrity, but I doubt it. Capps was ahead of the field by such a large margin that even with regression in his 2017 return he would be #1.

I am crazy for saying Carter Capps is the best relief pitcher in baseball. Or am I, really? If Capps pitches as well in 2017 as he did in 2015, just over a larger sample, I believe many of you will agree with me. Some of you may even agree with me after reading this.

So, let me be the first to say it: Carter Capps is the real best relief pitcher in baseball.

Sean is a student at Fordham University in Bronx, NY. He studies mathematics with a concentration in decision making and a minor in sports journalism. Occasionally, he submits articles to Fangraphs in the hopes that they aren't terrible. You can follow him on Twitter @srhkthew2.

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Capps certainly had a fantastic (part of a) 2015.

Let’s looks at some more numbers
Pitcher: K%, ERA, FIP, xFIP – Steamer Projected

Capps: 32.6%, 2.74, 2.69, 3.08

Chapman 38.7, 2.28, 2.33, 2.60
Miller: 38.4, 2.16, 2.02, 2.20
Kenley: 34.9, 2.68, 2.54, 2.94
Betances: 38.0%, 2.41, 2.28, 2.45
Britton: 28.3%, 2.43, 2.61, 2.64


Yea, I’ll take Kenley and his absurd consistent dominance.


Capps crow-hop pitch has also been made illegal. So he’s gonna lose some of that advantage now which should depress his #s.


Carter capps cheats. For some reason umpires have allowed him to get away with it. If he were ever on a team which made a serious postseasob run, the absurdity of the situation would force the unpires to come to their senses.