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Neglecting the lefties

The Phillies will go the entire 2017 season without using a left-handed starter. Surprisingly, this isn’t a rarity in Major League Baseball.

Philadelphia Phillies v Miami Marlins
Adam Morgan was the last left-handed starter to pitch for the Phillies ... on Sept. 28, 2016.
Photo by Mike Ehrmann/Getty Images

I didn’t think it was possible to go an entire season without using a left-handed starter. Baseball puts such an emphasis on having good left-handed pitching that I could not fully comprehend a statistic I saw just a few weeks ago.

Thus, upon hearing that the Phillies will go the entire year without having a southpaw start a single game, I was shocked. I checked it and was able to confirm. The 2017 Phillies, assuming a lefty doesn’t start in their last three games, will go the entire year without one, becoming the first Phillies team to do so since 1918.

The last left-hander to start a game for the Phillies was Adam Morgan on September 28, 2016, 163 games ago.

This might sound like a long time — but in the context of history, it’s not.

The Dodgers have two of the three longest streaks. They only started right-handed pitchers for 681 straight games spanning nearly five (!) seasons, from Sept. 24, 1992 to July 13, 1997. They also have the third-longest streak, a 454-gamer from 1902 to 1906.

The most recent streak of non-lefty starters was the Brewers’ from Aug. 28, 2013 to Aug. 19, 2016; this was 474 games.

The Phillies’ streak is the fifth-longest that I could even find, and I’m sure it’s actually much further down the list after seeing the disparity in games between No. 3 and No. 4. Finding a comprehensive list of these streaks was impossible.

It got me thinking though: how much are left-handed pitchers actually used in today’s Major League Baseball?

Between 8 and 12 percent of the world’s population is left-handed, but the number of innings pitched by southpaws is, in fact, much higher than this number. Let’s check out the innings pitched and percentage of total innings for lefties just for last 10 seasons.

Percentage of Innings by Left-Handed Pitchers

Year Total IP LHP IP RHP IP LHP %
Year Total IP LHP IP RHP IP LHP %
2017 42469.67 10909.67 31560.00 25.69%
2016 43306.00 11249.33 32056.67 25.98%
2015 43407.67 11684.67 31723.00 26.92%
2014 43613.67 11610.00 32003.67 26.62%
2013 43653.34 12574.67 31078.67 28.81%
2012 43355.34 12976.67 30378.67 29.93%
2011 43527.33 11603.00 31924.33 26.66%
2010 43305.33 12076.33 31229.00 27.89%
2009 43272.00 11856.67 31415.33 27.40%
2008 43357.67 12201.00 31156.67 28.14%

This is interesting. For the most part, lefties have thrown between 25 and 30 percent of a league’s total innings, despite making up between 8 and 12 percent of the population at large. It isn’t news that baseball emphasizes southpaws, but it is interesting to look at the extent to which they are emphasized. To me, I thought I would see a 60-40 split when looking at the numbers, as opposed to a 75-25 split that it turned out to be.

While left-handers throw significantly fewer pitches than right-handers, are they better? A fair amount of the best pitchers in baseball — including Clayton Kershaw, Chris Sale, Madison Bumgarner and Dallas Keuchel — are all lefties. The right-handed crowd gets to claim Max Scherzer, Stephen Strasburg and Corey Kluber. How much of an impact does handedness have on performance?

I considered only using starting pitchers in this study because I didn’t want LOOGYs or poor right-handed relievers to skew the data, but it wouldn’t be fair to either side to take out Craig Kimbrel (a righty) or Andrew Miller (a lefty). Thus, I used all pitchers.

Performance of Pitchers by Handedness

Year RHP ERA LHP ERA RHP wOBA LHP wOBA
Year RHP ERA LHP ERA RHP wOBA LHP wOBA
2017 4.42 4.19 0.322 0.319
2016 4.22 4.11 0.318 0.318
2015 3.98 3.91 0.314 0.312
2014 3.75 3.71 0.309 0.313
2013 3.90 3.77 0.314 0.312
2012 4.05 3.94 0.316 0.314
2011 3.96 3.90 0.315 0.318
2010 4.12 3.96 0.321 0.321
2009 4.37 4.20 0.329 0.329
2008 4.34 4.27 0.328 0.330

Left-handed pitching might be ever-so-slightly better in ERA, but the wOBA difference is minuscule, if anything. Despite there being fewer left-handed pitchers across the Majors, they really aren’t of superior quality.

And that makes sense. It’s fair to say that almost every single pitcher in the Major Leagues can throw 90 mph, so it isn’t like left-handed pitchers are being picked out specifically due to their handedness. Some of the leagues hardest throwers — I’m looking at you, Aroldis Chapman — are lefties.

While the number of pitchers able to throw 90 mph is increasing, this hasn’t always been the case. It’s possible that the quality of left-handed pitchers has increased in time, as training regiments have improved and velocities have gone up. It’s also possible that lefties have always been just as good as righties; the splits data for seasons before 2000 is hard to come by.

So are teams at a disadvantage by not starting lefties?

My gut says no. Left-handed starting pitching — as with left-handed pitching on the whole — is hard to come by.

While streaks like these are cool factoids, the impact of not throwing a lefty starter seems to be next-to-none.


All statistics are current through games played on Thursday, September 28, 2017.

Devan Fink is a Featured Writer for Beyond The Box Score. You can follow him on Twitter @DevanFink.