Checking in on Alex Cora’s aggressive approach

Alex Cora needs more credit for Boston’s offensive success

Featured image courtesy of (April 9, 2018 – Source: Maddie Meyer/Getty Images North America) 

Since Alex Cora’s introductory press conference as the Boston Red Sox manager,  he has been preaching an aggressive approach at the plate. Red Sox’ hitters were hindered by their passiveness in years past, watching too many hittable pitches go by for strikes. Cora wanted the team to change their “work the count” mindset to a “swing at strikes” one.

The thinking was that Red Sox’ hitters would benefit from being aggressive because they would swing and make contact with more pitches in the strike zone. During Boston’s 17-2 tear to begin 2018, the approach was clearly being implemented on a team-wide scale and it seemed to be working. Now, we are nearly halfway through the season, with 79 games in the books, and it feels like an appropriate time to check if Cora and Boston are still sticking with the aggressive mentality.

Are the Red Sox still swinging at strikes?

The entire point of this revamped style at the plate was for Boston hitters to swing at better pitches. So, in other words, swing at more strikes. Last season, under John Farrell, the Red Sox’ offense had the lowest Z-Swing% (percentage of pitches swung at in the zone) of any team in baseball at 62.3%. Ditto the 2016 season and in 2015 they were outdone by only the Oakland Athletics at swinging at less pitches in the zone.

Through close to half of a season of play, Boston now has the highest Z-Swing% in the American League at 69.4%. In Major League Baseball, they are second, trailing only the Atlanta Braves at 71.6%. The Red Sox have had the largest year-to-year jump in Z-Swing%, increasing their percentage by an incredible 7.1%.

More recently, though, they are starting to swing at less pitches in the zone. In the month of June, the Sox place 10th in Z-Swing% at 68.8%. Their placement in this category may be a bit misleading, however. The entire league has decided to swing at more pitches in the zone for the month of June (67.6%) compared to the rest of the year (67.1%). Perhaps teams are beginning to adopt this approach after seeing teams like the Red Sox be so vocal and adamant about it and the subsequent success they have had with it.

Regardless, a seven-percent increase in swinging at pitches in the zone, which are better to hit than ones outside of the zone, is nothing to scoff at. It has made a world of difference for the team’s performance. For the season, the team is third in baseball in wRC+ (109) and homeruns (109) while they place second in slugging percentage (.451). In contrast, last year they ranked 22nd in team wRC+ (92), 27th in homeruns (168) and 26th in slugging percentage (.407).

Correlation does not always equal causation but the enormous increase in offensive output has not been solely because of J.D. Martinez.

Has this aggressive approach hurt Boston in terms of plate discipline?

It has caused the team to strikeout a little bit more and walk a little bit less compared to last year, but nothing drastic. In fact, Boston has the 27th-lowest team K% this season at 20.2%. Boston also possessed the 27th-lowest team K% in baseball last season but it was at 19.3%. With that said, considering the league K% has risen from 21.6% in ’17 to 22.4% this year (0.8%), Boston is basically striking out at the same rate relative to the league.

On the other hand, the team’s overall BB% has fallen from 9.0% in 2017 to 8.2% this year. There has been no remarkable league-wide increase in BB%, jumping just 0.1% between 2017 and 2018. In spite of this, this year’s Red Sox team has the same OBP (on-base percentage) as last year’s at .329. Swinging at more strikes (better pitches) has enabled the Sox to run a higher average this year to make up for their decrease in walk percentage. Plus, the team is hitting for demonstrably more power this year, anyway.

Further, because they are more aggressive with the lumber, their O-Swing% (percentage of pitches swung at outside the zone) has risen quite dramatically.  This season they have featured the 7th-highest O-Swing% in the league at 31.0%. Meanwhile, last season they had the 16th-highest O-Swing% at 29.5%. In case you were wondering, the league-wide O-Swing% has risen 0.5% from 2017 to 30.4% in 2018.

Which Red Sox hitters are buying into this approach the most?

Excluding Hanley Ramirez from this list, here are the top-three hitters in Z-Swing% for the Red Sox this season with a minimum of 50 plate appearances: J.D. Martinez (80.0%), Rafael Devers (77.1%) and Mitch Moreland (73.0%).

Moreland and Devers were at the top of this list for the Red Sox last year, too. Martinez would have been at the top of this list for Boston last season if he were in a Boston uniform and would have been tied with Pablo Sandoval for the team-lead. More importantly, every single one of those guys has increased their Z-Swing% this year. Moreover, every single hitter, who has accumulated at least 50 plate appearances, has increased their Z-Swing% for Boston. Check out this table, showing every player’s 2018 and 2017 Z-Swing% and the year-to-year difference.

’18 Z-Swing% ’17 Z-Swing% Difference
Martinez 80% 76.4% +3.6%
Devers 77.1% 68.6% +8.5%
Moreland 73.0% 69.3% +3.7%
Nunez 71.8% 67.1% +4.7%
Bradley Jr. 71.6% 67.9% +3.7%
Benintendi 69.8% 64.5% +5.3%
Vazquez 66.7% 57.5% +9.0%
Leon 65.3% 62.5% +2.8%
Bogaerts 62.9% 53.0% +9.9%
Betts 59.9% 53.8% +6.1%
Holt 58.0% 55.2% +2.8%

The average Red Sox hitter has increased his Z-Swing% by an outstanding 5.5% this season. Xander Bogaerts has seen the biggest increase, despite still having one of the lowest Z-Swing% on the team. Vazquez and Devers have also seen their zone-swing percentage sky-rocket but they have not seen corresponding positive offensive production.

The lowest gains in year-to-year Z-Swing% have come from Holt and Leon, yet they still have seen it rise 2.8%. Every single hitter is buying into this approach, showing faith in their first-year manager. It is hard to get one guy to change their method at the plate, let alone the entire team. What Cora has done is truly remarkable.


Alex Cora‘s approach seems to be corresponding with improved results for lots of Boston’s hitters. Each Red Sox hitter has changed their approach at the plate and that is no small feat. This exemplifies the trust these guys have put into Cora and his philosophy.

This strategy has paid dividends for the Boston Red Sox, so there is absolutely no reason to stop now. Betts, Benintendi, Bogaerts and Moreland are all having career years at the plate and they have all improved their plate discipline, swinging at considerably more pitches in the strike zone. It is honestly astonishing to think of Boston’s offense last year compared to this one. They are polar opposites with virtually the same cast of characters, sans the otherworldly J.D. Martinez, of course.

This will be something to monitor as the rest of the season progresses. With that said, the Red Sox’ sustained offensive success may literally be dependent on this approach. This is not to say they do not have talented hitters, but just look at how those same talented hitters did last season, under the passive John Farrell strategy. Cora does not get nearly enough credit for the offensive success the Red Sox have experienced this year.

Patrick Green

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

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