Christian Yelich, Fly Balls, and a New Hope

Christian Yelich is a very good baseball player. Since becoming a full-time major leaguer in 2014, Yelich has accumulated 13.8 Wins Above Replacement, good for 35th among qualified hitters. Yelich owns a career 120 wRC+, showing he’s a fine hitter. Yet there has always been a lingering question: Can his bat be even better?

Yelich hits the ball hard. Since 2016, only 10 players have a greater average exit velocity (minimum 2500 pitches seen). More importantly, his 94.3 MPH exit velocity off of fly balls is 25th from the same group. If we add in line drives with fly balls, Yelich’s 95.7 MPH exit velocity ranks 17th, sandwiched in between Manny Machado and Yasmany Tomas. Exit velocity is only part of the story, though. His launch angle is not ideal. Despite hitting the ball more than a mile harder than sluggers such as Bryce Harper, Michael Conforto, and Anthony Rizzo, Yelich has routinely chosen a ground-ball-based approach. Since the All-Star break, we might have gotten another indication of a possible transformation. The prospects are tantalizing. Have always been tantalizing.

Last season, Yelich saw his wRC+ rise to 130, the best of his career. This was partly related to him increasing his power level, as shown by a .185 ISO, the highest of his career. No doubt like every other batter, he was aided by a mysterious force (most likely the ball), but he also had a slight approach change. Yelich hit more fly balls, and so far in 2017, he’s expanded on that. Yelich has the 35th highest (122 players) difference between his 2016 fly-ball rate and 2017 fly-ball rate (minimum 350 plate appearances in both seasons). Slowly, Yelich might just be embracing the fly-ball revolution. This is also seen in his launch angle. In 2016, Yelich’s average launch angle was 2.5 degrees. In 2017, it’s 4.9 degrees, nearly double (more on this later).

Yelich’s 15 Game Rolling GB% and FB%

Yelich seems to have committed to some sort of approach in which fly balls are more sought after. In September of last year, Yelich carried a fly-ball rate at nearly 30%. He began April hitting fly balls at a 27.2% clip, followed by 23.6% in May, and to a low 14.1% in June. He seemed to abandon the fly-ball approach as his results weren’t up to his standards. Have you ever done something you were excited about but didn’t do well that you sort of slowly stopped? I’d imagine something like that may have happened with Yelich. During the second half so far, his fly-ball rate is 32.3%! It could very well be the result of small sample size, but it could also be a sign of Yelich looking to become a better hitter. Since the All-Star break, the Marlins outfielder’s average launch angle has been 10.4 degrees. This is what we want to see. And interestingly enough:

Yelich’s 15 Game Rolling GB% and FB%

We haven’t really seen Yelich be at this power level. He’s had spikes for sure, but nothing as high as the power streak he has shown recently. It coincides with him lifting the ball more. Since the start of the second half, Yelich has a .250 ISO. To give you an idea of the type of power output, that’s pretty much what Anthony Rizzo and Miguel Sano have this season (both at .247).

This feeds into what I mentioned above with psychological factors possibly playing a role. Yelich is seeing good results; perhaps he may experiment a little more with a greater emphasis on fly balls.

As mentioned above, Yelich hits the ball hard. But he also hits it hard to all fields. This is just another example of the kind of strength that exists within Yelich and his all-fields approach making him a tough out. Being able to hit the ball to the opposite part of the park with authority is a rare skill. It’s one of the reasons why Rafael Devers is such an exciting prospect.

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Now combine that all-field power with solid zone control and you’ve got a good hitter. Then combine someone who is has a better batted-ball mix and you might just end up with a great hitter. If Yelich shows more power, which his 6’3″, 195lb figure suggests is there, Yelich will likely be given more free passes. Basically, Yelich has the tools to be that rare hitter than can hit for average and power.

Back to the launch angle which has nearly doubled — FanGraphs Andrew Perpetua recently had an intriguing article advising caution when using Launch Angle. In the article, Andrew writes, “Launch angle is largely dependent on the particular swing and approach of a given batter. If they have an uppercut, then they will produce high launch angles with their high-velocity balls. If they swing down on the ball, then they will have lower launch angles with their high-velocity balls.” Furthermore, Andrew mentions in the comments, “I think launch angle is so intimately tied with swing mechanics that you probably shouldn’t talk about it outside the context of swing mechanics.” This does make sense. Hitters need to alter their bat path to hit the ball at specific angles. Bringing it back to Yelich, we can try to see if he has altered his mechanics. Take the following with a massive grain of salt because it’s only a couple of videos, and I’m no swing expert. From the videos I’ve seen of Yelich, he seems to have a pretty smooth swing path and uses a leg kick for additional power. Here are two of his home runs this year: the first from June 2 against the Diamondbacks and the second from July 26 against the Rangers.

I don’t see a major difference. A bit of a stronger leg kick in the homer against the D’Backs.

In both of these videos, Yelich hits an opposite-field double. Against the Braves, Yelich seems to do a double leg kick. He did this in the next game as well. It’s not something that I’ve seen stick. I’d imagine it might have been due to seeing something he may not have been expecting. Either way, it must’ve been an interesting conversation between Yelich and the hitting coach.

From the limited video evidence, I can’t decipher much. Someone more experienced might want to look into it. The numbers show Yelich very well may have altered his bat path slightly.

One of the criticisms of Yelich was his lack of damage done when pulling the ball. He’s been the fourth-best hitter when going opposite field over the past three calendar years.

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On the plus side, this is another area of improvement for Yelich.

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Christian Yelich could very well remain a ground-ball-heavy hitter and be one of the better hitters in the majors. His plate approach has been lauded for many years to go along with his full-field power. If he is part of the fly-ball revolution, Yelich very well could be one of the best hitters in the game. He’s shown signs of a different approach. With the results to back it up, the rest of the season will give us a glimpse into the hitter that Yelich both wants to be and could be.