With the 2017 regular season finished and tallied up and the Rangers officially enjoying the offseason, Nomar Mazara’s future value remains a question. After a promising rookie season where he flashed impressive raw power and above average barrel to ball skills, he seemed prime for improvement going into 2017. Instead, after a brief hot streak at the beginning of the season, Mazara finished the season with .4 fWAR and .1 bWAR. Out of 144 qualified players, Mazara was sandwiched in between Alcides Escobar and Ryan Healy at 126th in fWAR.

Looking at Mazara’s peripherals, it appears that he took some small steps forward. His walk rate jumped from 6.9% to 8.9%, his K rate is within 1% of last seasons, his ISO saw a small increase, his hard hit rate is up to 32.6% from last year’s 28.7%, and aside from a 3% drop in HR/FB there wasn’t a dramatic shift in his batted ball profile. Despite these improvement his 2017 OPS is a clone of his 2016 performance. It leaves a question: what has kept Mazara from overall improvement?

Plate Discipline is the first culprit that is easy to quantify. Although Mazara has a cool demeanor and shows an increasing willingness to wait for his pitch, he can get overaggressive at times. His 32.9% O-swing isn’t crazy for a young hitter, but in addition to his struggles against the slider, it is a factor. Pitch recognition certainly could be a limiting agent for Mazara, but there are other hitters with his plate discipline profile who have put up good to great offensive careers.

Glancing at Mazara’s ground ball rate gives a bit of context to his middling ISO despite his impressive raw power. For 2017 his ground ball rate was 46.5%, which puts him in the top 40 highest ground ball rates. Ground ball rate alone isn’t enough to quantify a hitter though and while he’s in the same GB% echelon as Billy Hamilton (45.8% GB rate); he’s also right next to Paul Goldschmidt (46.5% GB rate) and Ryan Zimmerman (46.4% GB rate).

Aside from the distance in plate discipline and experience, what is making up the massive amount of space between Mazara and a productive hitter with a similar batted ball profile like Zimmerman that is more quantifiable than, “Zimmerman is obviously just a better hitter”? Mazara is still working with an advanced swing, excellent coordination, and plus bat speed. What else is contributing to the gap?

The newly minted “Barrel” stat gives interesting insight. A Barrel is simply a ball hit 98 MPH or harder at a launch angle that gives the batted ball an expected average >.500 and expected SLG% >1.500. The point is to see how much hard contact is being hit at a launch angle that is conducive to production. A grounder hit at 98MPH isn’t especially productive, while a ball hit 98MPH at a 28% launch angle can be a home run.

Mazara’s hard hit rates and average exit velocity are actually well above average. His batted ball velocities per baseball savant are close to Kris Bryant. While Mazara and Bryant are hitting the ball hard at a very similar rate, Bryant “Barreled” the ball 41 times while Mazara finished the season at a below average mark of 28. While Mazara is in the top 51 players in terms of hitting the ball 95 MPH or harder, he’s hitting quite a few at launch angles that don’t correlate with production.

The last question is, “why is Mazara not hitting the ball towards good launch angles consistently?” It’s likely a combo of needing to improve against off-speed and intent. Mazara looks to drive the ball when the pitcher gets behind in the count, but as soon as he has one strike against him, he looks to put the ball in play over driving the ball. With 0-1 or 1-1 counts, his ground ball rate jumps and his hard hit rate plummets. These trends are exaggerated on 1-2 and 2-2 counts. The exception is 0-2 counts where he seems to look to drive the ball again. For an extreme contrast, Joey Gallo’s batted balls stay consistent throughout every single count. While you might expect that to hinder his wRC+ when behind in the count, Gallo actually outperforms Mazara here, except for the aforementioned 0-2 count, despite a much higher strike out rate. This isn’t to suggest Mazara should completely throw away his 2-strike approach, but he should still be looking to drive the ball early in counts even when he does get behind.

Mazara still looks like a player who is primed for a big improvement; the data shows a player who is already skilled enough to be a well above average hitter, but is currently limited by his approach. If he can make the necessary adjustments to his approach in addition to general improvements that should come with increased exposure to the game, it’s still easy to see an exciting offensive profile.