Earlier this season High Heat Stats ran a wonderful article titled "Lightning in a bottle-- baseball's one-year wonders" examining the rarity of the fluke season in baseball. It really is a terrific article and I recommend you read it, but it just missed on something I was hoping to see. I wanted to know which of those one-year wonders was the least expected. Or, in other words, which was the flukiest?
I therefore set up a query to find which players have had the greatest difference between their highest WAR season and their second highest WAR season, assuming this gap serves as a more-than-adequate vehicle for establishing a sort of fluke rating to the more unexpected player-seasons in baseball's history.
First, using Baseball Reference's rWAR, I compiled a list of these greatest Outlier Seasons:
Greatest Outlier Seasons by rWAR
Obviously, Mike Trout's magical 2012 rookie season can only be compared to his very brief cup-of-coffee in 2011, so calling his season an 'outlier' is terribly unfair. But, as it stands right now, he is technically the leader until he posts the 11.5 WAR season everyone now anticipates in 2013 and proves to us he's not just another Billy Grabarkerwitz.
Grabarkewitz's 1970 season at #2 is the without a doubt the quintessential fluke season in baseball history. For those who aren't familiar with his story, it is one of the more fascinating career trajectories you'll find. His fleeting presence amidst the WAR leaderboards came just once as a 24 year old rookie, when he posted a 6.2 WAR with a 135 wRC+ from a premium position at the keystone. But in his following season Grabarkewitz struggled mightily. Hampered by injuries, he was only able to muster a mere 0.8 WAR in just 44 games. Over the course of his next five MLB seasons, ol' 'Grabs' never again breached that 1.0 WAR threshold he saw in that outstanding rookie season.
Jacoby Ellsbury is at #3, and I imagine this may be a bit controversial for some. Ellsbury had an amazing season we all remember in 2011 when he amassed 8.0 WAR as a 27 year-old. But beyond that one excellent season, Ellsbury hasn't displayed much of anything that demonstrates he is any better than an average center fielder. His 2nd highest WAR total sits at just 2.8 still, from back in 2008, and time is quickly running out for the speedy, one-sleeved Ellsbury with age 30 is lurking right around the corner.
Of course, Ellsbury hasn't had too many opportunities to prove his 2011 wasn't a fluke yet, with just 6 seasons under his belt heading into 2013. While other players in the top-10 like Terry Turner, Rico Petrocelli, Zoilo Versalles, Rick Wilkins, and Cito Gaston all had at least a decade to re-live their primes but failed again and again.
But while there is certainly a decent chance Jacoby is able to shake that fluke label in future seasons, I don't think it's necessarily a slam dunk by any means. He still would need another season of at least 3.6 WAR to remove him from this forgotten group of history's greatest flukes.
Fortunately for Red Sox fans, Fangraphs rates Jacoby's flukiness not quite so high as Baseball-Reference, but generally the two WARs agree on the top 10:
Greatest Outlier Seasons by fWAR
Darin Erstad's 2000 season leaps from somewhere below the top-50 rWAR outliers all the way up to the #4 slot in the fWAR rankings. Erstad hit for a .411 wOBA that year, yet in his nine seasons afterward he never again hit for anything higher than .335 wOBA. B-Ref credits Erstad with 39 fielding runs in 2002, contributing to a 6.1 WAR and keeping him off the rWAR fluke list. This is a whole lot more than Fangraphs' UZR estimate of only about 17 runs, and therein lies the heart of the discrepancy.
But beyond Ellsbury and Erstad, what are some of the more recent 'fluke' seasons?
Recent Outlier Seasons by rWAR
Yadier Molina's amazing 2012 season is likely to get him at least a few MVP votes, but it's also landed him into a bit of fluke territory, considering his 6.7 WAR this season bests all of his previous campaigns by at least 3.8 Wins. Molina will be looking to repeat his success in 2013, no doubt, and avoid the fate of, say, a Daric Barton, who after a terrific all-star caliber season in 2010 has just about fallen off the face of the earth since.
I certainly am not surprised by Ryan Ludwick, Franklin Gutierrez, or Chone Figgins making this list, these are exactly the names I was hoping to find and seeing them here only vindicates the method. But I will admit the appearance of Sammy Sosa did surprise me a bit. Sosa did have that excellent peak from 1998-2002, where he averaged a little over 6 WAR per season, but his 2001 season was so far and away beyond the level of play he had seen before, it rightly gives us the justification to cry fluke.
Fangraphs' version of recent fluke seasons has a couple more surprising names for our entertainment:
Recent Outlier Seasons by fWAR
Andres Torres was in many ways the 2010 World Series Champion San Francisco Giant's secret weapon that season. Meanwhile, in the opposing dugout that series the the Texas Rangers had enjoyed the fruits of their own outlier in-- what's this? Josh Hamilton? That's right, according to fWAR Josh's 2010 season was not at all like the others, to the tune of at least 4 WAR. Obviously, Hamilton's rate-stats have been steadily MVP-caliber for many years now, but his problems remaining on the field have unfortunately branded him with the fluke tag here.
Buster Posey, something tells me, is probably not finished posting +4 WAR seasons, so his status on the fluke meter should drop before long. And 2012 darling Ian Desmond needs only to post one season of at least average value and he too will erase his name from this dubious list. Matt Kemp's 2011 season just missed the list at #11, incidentally.
Before I leave you, I'd like to link you to two google docs detailing the top-50 Outlier Seasons according to both WAR metrics for your amusement, dismissal, or ridicule:
(Honorable mention for #29 rWAR and #22 fWAR outlier Jim Gentile who jumped to 6.7 WAR in his excellent 1961 season, but unfortunately was out-shined by another much flashier, media-friendly narrative that year.)
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