What is an ace? Three year sample.— Camden Depot (@CamdenDepot) May 2, 2017
I chose those four options with a purpose. When we generally think about aces, we think about long term performance and, for most general managers, three years is a payoff window you expect when you throw down big money on an arm. During that time, you expect a solid cumulative performance, but also the idea that the pitcher will not give you a trash season. Below is the grouping of pitchers who qualify from 2014 through 2016 using fWAR.
The Highlander Model
18 WAR total
Minimum 5 WAR per season
There can be only one. This model was a distant second behind first and just barely finished above third. This model is quite exclusive. While six pitchers qualified under the cumulative condition, only Clayton Kershaw (22.7/6.5+) and Corey Kluber (18/5.1+) passed the muster on maintaining a 5+ WAR per season. If I had a fifth option, it would have looked like 21/6+, which Kershaw would have hit. Regardless, a minimum 5 WAR season is typically a top 10 starting pitcher performance and clearly an upper tier first rotation slot starter.
Kershaw really stands alone here, but that is not exactly historically unique. In the past twenty years, ball slinging luminaries such as Pedro Martinez, Curt Schilling, Johan Santana, and John Smoltz never climbed to this rarified air. However, from 1990 until Kershaw's brilliance, we can sprinkle in brilliant campaigns by Roger Clemens, Greg Maddux, Randy Johnson, Roy Halladay, and Cliff Lee. There is only a stretch in the mid 2000s where no one was at this mark.
In other words, the 18/5+ is a model that is the beginning of the third act of Highlander. The 21/6+ is the model that is the end of the third act of Highlander.
The Raubritter Model
15 WAR total
Minimum 4 WAR per season
By far, this definition won the poll with over 50% and no need for a second round run off. This level takes its name from the German word originally used to create the term Robber Baron. These pitchers run the pitching world and there are enough of them to populate a gentleman's club with a poorly made lake lying above a series of large towns. A minimum of 4 WAR per season tends to mean that every one of those three seasons, the player was an above average first rotation slot starting pitcher.
Kershaw and Kluber rule the roost here, but David Price (17.3/4.4+), Max Scherzer (17.0/5.2+), and Chris Sale (16.6 gain entry/5.2+). This grouping is one with which there are no obvious weak links. All are exceptional hurlers who you never really expect to come into a game performing sub-optimally. Below this run, you begin to run into a few pitcher, while quite exceptional, have some red flags to wave from time to time.
The Kumite Model
12 WAR total
Minimum 3 WAR per season
Kershaw is Frank Dux, Kluber is Ray Jackson, and Sale is that punk Chong Li. Price and Scherzer also play major roles. However, this needs to be a full length film and few of the actors can speak well and the dialogue is wretched, so lets add.six more fighters. On come Madison Bumgarner (14.1/4.0+), Jacob deGrom (12.0/3.2+), Johnny Cueto (14.2/4.1+), Jose Quintana (14.6/4.8+), Jon Lester (14.9/4.3+), and Jake Arrieta (16.1/3.8+). At a 3 WAR plus level, the minimum performance is within the top 30 starting pitcher performances each year. This is a level where every pitcher has given at least a respectable first slot performance.
At this point, the club no longer feels all that exclusive. There are only 11 aces though, which means when parsed evenly almost two thirds of MLB would be without elite pitching. That might make you think that we are currently in a state of poor pitching talent, but this definition (while normalizing for innings pitched) actually is rather consistent over time. Additionally, you have players like deGrom, Cueto, and Bumgarner who sometimes seem completely lost when entering a game. It is not a common occurrence, but there feels like with this group that you might have a decent chance at times.
The Oprah Model
9 WAR total
Minimum 2 WAR per season
You get an Ace! You get an Ace! Everybody gets an ACE! Well, not quite. Almost everybody gets an ace and some clubs get two or maybe three. It depends on the year.
| cWAR | Min | |
| Zack Greinke | 12.3 | 2.2 |
| Dallas Keuchel | 12.2 | 2.7 |
| Stephen Strasburg | 11.8 | 3.4 |
| Chris Archer | 11.5 | 3.1 |
| Cole Hamels | 11.4 | 3.0 |
| Justin Verlander | 11.0 | 2.9 |
| Gerrit Cole | 10.2 | 2.3 |
| Carlos Carrasco | 10.1 | 2.5 |
| Masahiro Tanaka | 10.0 | 2.3 |
| Collin McHugh | 9.9 | 3.0 |
| Gio Gonzalez | 9.8 | 2.9 |
| Jeff Samardzija | 9.3 | 2.6 |
| John Lackey | 9.2 | 2.5 |
At this level, you see some guys where there are arguments about whether they belong to the next class. Pitchers such as Zack Greinke, Stephen Strasburg, Chris Archer, Cole Hamels, and Justin Verlander sound vaguely like ace pitchers and certainly have enjoyed seasons where it would be a given assumption. The baseline for this group is well below first slot pitchers. The 2 WAR minimum doubles the pitcher pool from Kumite model, so the worst that anyone has performed in this group is as a below average two slot starter. Only four of the new batch remained above the first slot 3.0 WAR red line.
Conclusion
In the end, I think the crowd was quite wise on this question and I think this also shows how well WAR is being incorporated in common sense baseball assessment. Most people chose a definition that would define only five pitchers as Ace pitchers. That passes the sniff test for me. For instance, you can expect about 15 pitchers having a WAR above 4 in a single season. However, to do that three seasons in a row, it collapses that group by about two thirds. That ability to be a dependable top flight pitcher is what I would call an ace.
Bring on the Raubritters.
