The 2018 Red Sox have stopped hitting so many infield flyballs

Featured image courtesy of (May 28, 2018 – Source: Maddie Meyer/Getty Images North America)

It seems like a lifetime ago when the Red Sox were a bad offensive team. Remember last year when they were last in the American League in homeruns? They have completely reinvented themselves this season, hitting for power and contact. Alex Cora came in and preached swinging at better pitches and so they have. It has paid dividends, as the team leads the league in runs scored (591) and ranks second in wRC+ (112).

During the endless 2017-2018 offseason, this author investigated some explanations for Boston’s lack of offensive production. Obviously, not having David Ortiz for the first time in over a decade hurt but there was much more to it. Players who had hit at a well above-average rate in 2016 had regressed significantly the following season.

It was dubious and alarming, putting a damper over the 2018 Red Sox outlook. Well, again, look at them now. This is the best regular season Red Sox team since, at least, 1946. The offensive resurgence can be accredited to multiple things: J.D. Martinez, regression to the mean and improved pitch selection. With that said, the Red Sox have also stopped hitting infield flyballs at the prolific rate they did in 2017.

In early March, I wrote a piece titled The 2017 Boston Red Sox and infield fly ballsfinding that Boston led the American League with an 11.4 IFFB% (infield fly ball percentage). This is bad because, outside of strikeouts, infield fly balls lead to outs more than any other plate outcome. In the game of baseball, hitters do not want to make outs, so you should see the problem.

The season prior they also placed in the top five in this category. Even so, the 2016 Red Sox were able to overcome the near automatic outs they were forfeiting, as they were a great offensive team. A club hitting a bunch of infield flyballs does not have to dismantle an offense but it is probably good to not lead the A.L. in them.

In 2018, the Alex Cora-led Boston Red Sox have dropped its IFFB% to 9.5 percent, which is 23rd in all of baseball. They have eliminated nearly two percent off these weakly hit batted ball outcomes. While infield fly ball percentage is calculated out of total fly balls and not all batted balls, it is still impressive the 2018 Red Sox have increased its fly ball percentage (34.4% in ’17 to 35.8% in ’18) and shaved off two percent of its infield flyball percentage.

Anecdotally, it makes sense that the Red Sox are hitting less infield fly balls. Boston has increased its Z-Swing% (percentage of pitches swung at in the strike zone) dramatically this season, as they are making contact with better pitches and thereby less contact with worse pitches. Consequently, they have a lower percentage of infield flyball percentage. Now, a ball does not have to be outside of the strike zone to end up an infield flyball but it certainly makes it easier.

It seems like improved pitch selection has had a tremendous affect. It also does not hurt, as mentioned in the March blog, that Pablo Sandoval and Chris Young were removed from the Red Sox. They were two of the three biggest IFFB% offenders for Boston in 2017.

Further, the article focused on Mookie Betts as a statistical representative of increased IFFB% over the years. He ran a 10.5 IFFB percent in 2015, which is above league average, but it shot up to 14.8 percent in 2017. Betts had the 17th-highest infield flyball percentage among qualified players in a season when the league-average IFFB% was 9.6.  This year, however, he has brought it down to a much more desirable level at 10.9 percent. While the team has knocked off two percent, Betts has dropped his IFFB% by four percent.

The Boston Red Sox have been firing on all cylinders this season. It all started with a new approach at the plate and the addition of one of the greatest hitters in baseball. The fact they have stopped hitting infield fly balls at the rate they did in 2017 has contributed to greater offensive success in 2018. They are no longer giving up as many free outs, which is conspicuously a positive.


Patrick Green

Founder and owner of Red Sox Unfiltered. Communications major at UNCC.

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