Setting expectations for Christian Yelich in 2019

Saying that Christian Yelich was really good last year does not do his season justice. Calling his season excellent may still be an understatement. It’s tough to find a word to describe how incredible Yelich’s debut season in Milwaukee was.

Last January, the Brewers parted with a significant package centered around their top prospect, Lewis Brinson, to acquire Yelich from the Miami Marlins. Expectations for the outfielder were understandably high. Yelich got off to a great start, hitting for an .823 OPS and 122 wRC+ with 11 home runs in the first half of 2018. It wasn’t superstar production, but it nonetheless earned Yelich a selection to the All-Star Game.

That’s when things got wild. There was always the question of what Yelich could be capable of if he ever discovered some untapped power. He did exactly that. After drilling an opposite-field homer in the Midsummer Classic, Yelich then proceeded to turn into an unstoppable force for the remainder of the season. In the second half, he raked to the tune of an absurd 1.219 OPS and 220 wRC+. He hit 25 home runs in that span, which was more than his previous career high of 21. He slugged .770 in the second half; the league-wide OPS in 2018 was .728. Yelich also made history by hitting for the cycle twice against the same team—the Cincinnati Reds—within three weeks. When the regular season drew to a close, Yelich finished with the best wRC+ (166) and OPS (1.000) in the National League while demolishing 36 home runs. He completely shattered the already-high expectations that the organization and fans had for him. Yelich had reached the ceiling that baseball pundits had dreamt of for years.

Thanks to Yelich’s monster performance, the Brewers surged in September to force a tiebreaker game with the Cubs for the division. Milwaukee would win the game and was crowned division champions. After sweeping the Rockies in the NLDS, the Brewers fell one win short of a World Series appearance. It was a bitter ending, but the whole ride was nothing short of magical, and Yelich was right in the middle of it. His incredible performance resulted in a Silver Slugger award and a near-unanimous NL MVP selection.

Unfortunately, it’s not sustainable. Yelich isn’t going to hit for a 220 wRC+ next year or have a slugging percentage higher than the league-average OPS. What should we expect from him in his second season in Milwaukee?

At this point in his career, it’s safe to say that Yelich’s floor is something close to how he performed in the first half. Prior to the 2018 season, he carried a career OPS of .800 and a 122 wRC+. He also had a well-above-average BABIP of .356. While a high BABIP typically indicates fluky performance in smaller samples, it doesn’t really mean much if it is sustained over several seasons, as is the case with Yelich. His first half was largely in line with those career marks, as he posted a .823 OPS, 122 wRC+, and .363 BABIP. At the very minimum, Yelich ought to be able to replicate those numbers.

Here is where it gets interesting: delving into Yelich’s second half. More specifically, how legit was his sudden power surge? Let’s begin by checking his batted ball profile in each half.

A few things stand out when looking at these numbers. First of all, while Yelich continued to hit grounders at a high rate, he did slash his ground ball rate by about five percent. Those grounders turned into fly balls, which is a typical explanation for a power increase. However, it’s not enough to explain why Yelich suddenly started smashing homers left and right.

Secondly, Yelich was already hitting the baseball hard an awful lot in the first half, but he somehow managed to do it even more frequently in the second half. A hard contact rate of 50% is elite.

Lastly, Yelich’s HR/FB rate experienced a gargantuan spike. Nearly half of the fly balls Yelich was hitting were leaving the park. How did he do that?

In October, Jeff Sullivan wrote a fine piece over at FanGraphs that looked into Yelich’s second half. What he noted was that Yelich’s launch angle only increased by about two degrees in the second half, which really isn’t much of a change at all. Rather, the power surge was more so a result of his increased amount of hard contact. Yelich’s launch angle on batted balls hit 100 miles per hour or faster was higher than ever before. Sullivan notes that Yelich’s launch angle on such balls in play jumped by about 10 degrees compared to his first half; only Jorge Alfaro had a higher increase.

We can check the Statcast search tool ourselves to get more information about this. Yelich’s second-half launch angle on batted balls of 100 miles per hour or greater was 14.7 degrees. That was 92nd in baseball during that time frame (minimum ten such results) and was tied with Mookie Betts, J.T. Realmuto, and Mitch Moreland. Yelich hit 78 balls at an exit velocity of 100 miles per hour or more in the second half, which was the most in all of baseball during that span. The next closest was Manny Machado with 72.

According to the batted ball data at FanGraphs, Yelich’s hard contact rate on fly balls was a whopping 67%. That ranked first in all of Major League Baseball. Once again, there was a notable increase between halves. In the first half, 62.7% of his fly balls were classified as hard contact. That already ranked third-best in the game. In the second half, that rate jumped to 71.2%. Yelich may not have been hitting fly balls often, but the ones he did hit were crushed, especially in the second half. When you add all of these bits of information together, it all starts to become clearer.

To sum it up, Yelich hit the ball hard at an even higher rate than he did in the first half. More specifically, his second-half fly balls were hit harder and with a higher launch angle than ever before. When you add all of that together (along with a touch of good luck), you get a HR/FB rate that jumps by nearly 30%. Yelich was crushing baseballs like he never had before, and he didn’t have to adopt a fly-ball-heavy approach to find his power.

That’s how he pulled it off. With this knowledge, we’re back to the original question: what should the expectations be for Yelich next season?

Yelich is always going to hit plenty of ground balls, and he’s always going to run a high BABIP. By this point, it can be safely assumed that Yelich’s ability to find holes on ground balls is simply a testament to his strong offensive abilities, not just some fluky success driven by luck. It’s always going to be an important element of who he is as a hitter.

How sustainable is the power? Yelich finished the season with a 35.5% HR/FB ratio. That led all of Major League Baseball, with J.D. Martinez coming in second with a 29.5% mark. Yelich isn’t going to keep hitting fly balls over the fence at the same rate as last season. To illustrate this, here are the most recent players to manage a HR/FB rate of 30% or higher in a season, and how that rate changed the following year:

The only somewhat recent player to consistently post a HR/FB rate over 30% was Ryan Howard, who did it for four consecutive seasons (2005-2008). It’s difficult to manage such a high rate for even one season, which is why the list of recent examples is rather short. Most of the few who do pull it off see their HR/FB ratio drop back down to the mid-to-upper 20’s the following season. Other examples of players who have done it in the 21st century are Jim Thome, Barry Bonds, Manny Ramirez, and Sammy Sosa, but even they couldn’t manage to do it for more than one season at a time. Unless he turns out to be one of the best power hitters of the generation, Yelich is not going to repeat his HR/FB rate from last season.

However, Yelich’s improvements aren’t fake. You don’t make hard contact half of the time on accident; that’s skill-driven. Yelich will be only 27 years old next season, so there’s no reason to believe that his excellent rate of hard contact will suddenly plummet. Furthermore, Yelich is playing his home games at hitter-friendly Miller Park, so he’s going to hit more fly balls over the fence than he did during his time in Miami. It’s perfectly reasonable to expect Yelich to post a HR/FB rate around 25% next season. That would be a fairly significant drop from his 2018 rate, but it would still be higher than his career rate. It would also be largely in line with how other players have followed up seasons with a HR/FB rate over 30%. According to FanGraphs, Yelich hit 103 fly balls last season and 118 the prior season. If that continues again next year, he could still finish with about 25 home runs, and a chance of him reaching 30 again cannot be ruled out.

Yelich’s power numbers are all but guaranteed to trend downward a tick next season, but there’s more to a player’s production that how many home runs he hits. What about the rest of his offensive numbers across the board?

DRC+ is also a helpful tool for trying to predict how Yelich will fare next season. The new stat was never particularly bullish on him. Below is yet another chart. This one displays how Yelich’s DRC+ has stacked up against his wRC+ throughout his career:

For much of his career, DRC+ has viewed Yelich as an average—or even slightly below-average—hitter. That changed in 2018, as Yelich posted a career-best 145 DRC+. Because it accounts for more factors than any other offensive stats, DRC+ is arguably the most predictive stat available. DRC+ indicates that some of Yelich’s success was luck-driven (which is often the case when you have a season as good as his), but it does agree that he made significant improvements as a hitter. Based on this, he’s highly unlikely to revert all the way back to his 2013-2017 form. Rather, Yelich will once again be one of the better hitters in the National League next season. Steamer agrees with this assessment, as it is projecting Yelich to hit for a 140 wRC+ and .895 OPS with 27 home runs. All things considered, that projection will likely prove to be accurate.

It’s likely that we just witnessed the best season of Christian Yelich’s career. However, that does not mean he’ll return to being the same player he was before. Yelich hit the ball harder than ever before, and as the season progressed, he turned that hard contact into booming fly balls. The result was a power tear that Yelich had never before approached in his career. While it’s highly unlikely that he’ll repeat that home run binge next season, Yelich’s newfound power is likely here to stay. He may not put up MVP-level numbers again next season, but he’ll still be one of the league’s better hitters, and he will be right in the middle of Milwaukee’s quest for a World Series title this coming summer.

Statistics courtesy of FanGraphs, Baseball Savant, and Baseball Prospectus.