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Making An Ace, Part 2: Identifying The Aces

Last week, we defined what an “ace” means. Today, we select the aces we want to analyze.

Houston Astros Photo Day Photo by Rob Carr/Getty Images

This is part two of my series, “Making An Ace”. Last week, we discussed the definition of an “ace” and have come to an overall conclusion. This week, we will select the aces we will analyze next week for our study.

We’re continuing our study on aces this week. Last week, we had some discussion on the definition of what an “ace” means in baseball. We had two glossary-style definitions, one from and one from Wikipedia. However, the fans have a different definition of what an ace is:

The overwhelming pick for an “ace” was the BEST pitchers in baseball, regardless of where they are on a given rotation’s order. This should make sense, too, as an “ace” should be about skill and it’s what is most commonly used in baseball talk; this poll more-or-less confirms that.

What that in mind, it seems that we shall go forward in identifying an ace as pitching multiple seasons with at least a 120 ERA+ and qualified for the ERA title (which simply means pitching 1 IP for every game; in other words, 162 IP for a full season). There are other, more specific ways we can define this (such as setting K/9 and BB/9 limits) but it doesn’t really seem necessary for this exercise. Run prevention is effective enough of a limit, especially over multiple seasons.

To keep things modern, we’re going to start with the past 10 seasons worth of pitchers. If we identify enough pitchers, we’ll leave that cutoff there for now. Off to Baseball-Reference’s Play Index finder to find pitching seasons of 162+ IP and 120 ERA+ between 2009 and 2018:


This table is simply too long to post here: there are 130 pitchers that have done this at least once in the past 10 seasons and a total of 252 player-seasons of 162+ IP and 120 ERA+ or better. That is just over 25 “ace-like” player-seasons per year, which seems to be a pretty healthy amount (and in line with the guess of “15-25 aces at a given time” in the poll).

Of these 130 players to accomplish this, a whopping 69 of them only did it once. They had “ace-like” seasons but considering the sheer volume of pitchers here, it seems like it’s not enough to keep them in the study. To be fair, some of these 69 pitchers accomplished it for the first time last season, so maybe they will be aces down the road, but for now, they are not.

From here, there are an additional 35 pitchers that accomplished this twice in this time frame. These guys are certainly getting closer, but for the sake of this exercise, we will not include them at this time. Let me know in the comments if you disagree with the cutoff.

So, without further ado, that leaves us with our 25 aces from the past 10 years:

3 Times

  • Roy Halladay
  • Jered Weaver
  • Hiroki Kuroda
  • James Shields
  • Johnny Cueto
  • Madison Bumgarner
  • Ervin Santana
  • Sonny Gray
  • Lance Lynn
  • Jake Arrieta

4 Times

  • Matt Cain
  • CC Sabathia
  • Adam Wainwright
  • Gio Gonzalez
  • David Price

5 Times

  • Felix Hernandez
  • Cliff Lee
  • Chris Sale
  • Corey Kluber

6 Times

  • Zack Greinke
  • Jon Lester
  • Cole Hamels

7 Times

  • Max Scherzer

8 Times

  • Clayton Kershaw
  • Justin Verlander

There might be a few question marks in the 3 times crowd but it’s absolutely solidified with the pitchers that achieved this 4 times or more. I think this exercise also shows how difficult it is to be a starting pitcher. Think about it: in the past 10 years, only 10 pitchers have been able to pitch a full season with an ERA that is 20% better than average at least 50% of the time. That’s a really, really small number.

Check back next week as I start diving into these pitchers. Where did they come from? How long were they in the minors? How good were their minors stats? Is there anything that these pitchers have in common statistically? We shall find out!