If the headline of this piece didn't betray my motivation for posing the following question, I'd probably begin this article with a poll. Over the last 365 days, who, by the reader's estimation, has been the best pitcher in the American League? There are names of obvious ace starting pitchers, but anyone answering that question might be surprised by doing some research.

A portion of the audience might filter qualifying starters by FIP and select David Price (3.12) - although his rocky start in Boston might make that mocked as a shallow selection. Others might go with the tried and true Chris Sale or Corey Kluber - big names that actually appear in the top 10, but not at the top, of most major categories. Some readers might sort qualifying starters by ERA, and be surprised to find Danny Salazar (2.79) or Marco Estrada (2.85) as their selection. Context neutral versions of the above inflate Jose Quintana's bid for greatness (74 ERA-, 75 FIP-).

However, I suspect that the majority of sabermetric readers will instead sort their leaderboards by their preferred flavor of WAR. RA9-WAR again provides the somewhat surprising combination of Estrada, Salazar, and Quintana. However, the version I'm a bit more interested in is FanGraphs' own fWAR. Sitting at the top of that list? Detroit Tigers ace, Justin Verlander.

Name IP ERA FIP RA9-WAR WAR Justin Verlander 228.0 3.39 3.33 5.4 5.7 Jose Quintana 216.2 3.12 3.25 6.2 5.5 David Price 211.2 3.70 3.12 5.0 5.2 Corey Kluber 218.2 3.58 3.25 4.3 5.0 Chris Sale 221.1 3.70 3.49 4.2 5.0 Collin McHugh 198.2 3.85 3.48 3.9 4.4 Dallas Keuchel 214.2 4.02 3.57 3.4 4.4 Masahiro Tanaka 199.1 3.25 3.68 5.3 4.0 Danny Salazar 199.2 2.79 3.51 6.3 3.9 Hisashi Iwakuma 222.2 3.56 3.78 4.6 3.7

Considering some of the reactions I received after posting this fun fact on Twitter, this is maybe even a bigger surprise than some of the names mentioned above. He had a disappointing 2014 season and an injury-plagued 2015. Combining those factors with his place on the aging curve and a notable loss in velocity, many thought that a dominant Verlander was firmly in the past.

However, since returning from the disabled list in June 2015, Verlander has actually regained about half a mile per hour on his fastball, and he's pitched the most innings of any AL pitcher over the past calendar year. As was noted elsewhere on the internet, rejuvenated performance followed, and some opinions were changed. Then, 2016 began with six poor starts, totaling a 6.49 ERA and 5.02 FIP over 34.2 innings pitched.

But yet again, the twelve starts since have seen a remarkable turnaround, where Verlander has struck out 26.4 percent of batters faced while keeping walks low and produced a 3.05 ERA. Now, this isn't some examination of his delivery or individual pitches to explain away the up-and-down nature of these individually small samples. Instead, I'm more interested in how, in total, Verlander ended up at the top of this leaderboard unexpectedly, with numbers that don't pop off the screen as "best starter in baseball" material - at least in the recent context.

Immediately, some will probably have problems with the choice of WAR - however, even using RA9-WAR, Verlander still comes in fourth and within a win of the leader (Estrada). This isn't a case of a pitcher being overrated because of his peripherals. The run-prevention argument would more accurately state that Salazar, Estrada, and Quintana are being underrated for one reason or another.

In the above leaderboard, one might notice that Quintana slightly edges out Verlander in ERA and FIP but still trails using FIP-based WAR. Given similar walk and strikeout rates and a significantly higher ground ball rate over this time, no one would mock a person for picking Quintana over Verlander as the better performer. However, the slight difference presented in fWAR comes from a couple factors.

Most basically, Verlander has roughly 1.5 starts worth of innings more than Quintana over this time, and were their FIPs equal, that alone could put him up by a fifth of a win. Second, while both see plenty of benefit from generating pop-ups, Verlander has generated significantly more over the last year. In fact, he is third behind only Marco Estrada and R.A. Dickey on the leaderboard for IFFB percentage over the last calendar year. This is significant for fWAR because infield fly balls are added to the strikeout total when calculating FIP for this purpose, and those are not represented in the standard FIP figure. Verlander actually receives extra (or, appropriate) credit for those events beyond what the raw figure describes.

So, he's got the innings pitched and a FIP bolstered by infield fly balls. Still - a 3.33 FIP/3.39 ERA combination doesn't scream "best pitcher in the league." Part of that is probably explained by the widely noted increased run environment - in the AL, teams are on pace to score more runs per game than in any year since 2009. It makes sense that we might need to readjust expectations to the run scoring environment.

AL R/G NL R/G MLB R/G 2009 4.82 4.43 4.61 2010 4.45 4.33 4.38 2011 4.46 4.13 4.28 2012 4.45 4.22 4.32 2013 4.33 4.00 4.17 2014 4.18 3.95 4.07 2015 4.39 4.11 4.25 2016 4.61 4.41 4.51

What still seems weird about Verlander's totals is that 5.7 fWAR is the best of any pitcher in the league over a full season. Over in the National League, Clayton Kershaw has already totaled 5.5 fWAR in 2016 (admittedly, an unfair comparison). But even still, the figure seems a little low. Looking at both the NL and AL fWAR leaders for every season since 2000, none of them (out of 32) produced 5.7 wins or fewer. However, Kershaw in 2012 came close with 5.9 fWAR in the NL, and several hovered around 6.0 wins - it is feasible to toss this up to using random endpoints and some luck.

However, many of the league's premiere pitchers are currently in the NL. Of the top five fWAR totals over the last calendar year, four - Kershaw, Jake Arrieta, Max Scherzer, and Noah Syndergaard - are in the National League. It seems that at least for this moment, there's a slight imbalance between the leagues when it comes to elite-level pitching.

Verlander is a little bit fortunate for these purposes, in that this "season" happened to fall during a time when other traditionally elite pitchers are either in the National League or inconsistent (Price and Sale). Further still, it was also luck that I happened to sort the leaderboard on that particular day, as Quintana could feasibly catch up with a good start, and Verlander would have fallen back if his ugly outings from late June 2015 had fallen within the date range.

Regardless, Verlander has proven his durability, is striking out more batters, and is performing at a rate close to his production in 2012-2013. Whether or not he's literally the best pitcher in the American League is a bit beside the point - a good Verlander is exciting to watch, and that's certainly good for baseball.

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