Why Isn't Christian Yelich Hitting for Power?

After a breakout campaign that included a career-high 21 home runs in 2016, Yelich's power numbers have regressed this season.

The Miami Marlins are fortunate to have a ton of talent in their outfield. With guys who can grab headlines like Giancarlo Stanton and Marcell Ozuna, though, it's not always easy for Christian Yelich to get himself front and center. Despite that, he did a pretty good job of getting the attention of those outside of Miami in 2016.

While he hasn't yet been to an All-Star game, Yelich did finish 19th in National League MVP voting last season, ahead of his fellow Marlins outfielders. That was made possible by a career year at the dish, which included a solid .298/.376/.483 triple slash in 659 plate appearances, and his new single-season career highs in wRC+ (130) and wOBA (.367) were engineered by an emergence of power.

Through his first 1,442 plate appearances in the big leagues, Yelich hit 20 home runs and posted an Isolated Power (ISO) of .115. But in those 659 trips to the plate last year, he collected 21 bombs and bumped his ISO up to .185. Looking at the progress he made and knowing he'd be entering his age-25 campaign in 2017, it wouldn't have been crazy to tab him as an under-the-radar NL MVP candidate.

But with 317 plate appearances under his belt so far this year, it hasn't been the same story -- he has hit 7 homers, but his ISO is down to .120 to go with a .274/.354/.394 triple slash, 99 wRC+ and .325 wOBA.

Still Doing a Lot of the Same Stuff

Even with the 2016 power surge, Yelich's batted-ball profile hasn't really changed a whole lot over the years. Since debuting in 2013, he's always hit a ton of ground balls and not that many fly balls. The below table shows how his line-drive rate (LD%), ground-ball rate (GB%), fly-ball rate (FB%), and hard-hit rate (Hard%) have looked each year as a big leaguer.

Year PA LD% GB% FB% Hard%
2013 273 23.0% 63.2% 13.8% 34.3%
2014 660 21.2% 61.0% 17.8% 34.2%
2015 525 22.5% 62.5% 15.0% 33.1%
2016 659 23.4% 56.5% 20.0% 38.0%
2017 317 20.8% 57.5% 21.7% 35.6%

There have been some changes so far in 2017, but they're not overly drastic.

To put this in perspective, the 59.9% ground-ball rate he's produced since debuting is second-highest in baseball (trailing only Nori Aoki's 61.0%), and his 17.9% fly-ball rate is the lowest. So, the batted-ball profile he boasts so far in 2017 isn't anything particularly noteworthy.

What has changed, though, is the quality of contact he's making -- particularly when it comes to fly balls.

Except When He Hits Fly Balls

It's not uncommon to have line drives turn into home runs, but that mostly depends on the type of hitter. For Yelich, his homers basically only come on fly balls -- only one line drive has left the yard in his career, which happened last season.

With that in mind, it's important to take a peek at how he's performing on fly balls when compared to his breakout campaign to see if there are any huge differences. And there sure are.

As touched upon earlier, Yelich doesn't hit a ton of fly balls, meaning that when he does, he needs to make the most of them. Between 2013 and 2016, he did just that -- he never produced a wRC+ on fly balls lower than 225 (including a career-high 353 in 2016) or a wOBA below .498 (including a career-high .699 last season).

So far in 2017, though? He's produced a 155 wRC+ and .410 wOBA on fly balls, both of which are clearly on pace to be career lows. If we just scroll down a little further, the biggest change from the first four years of his career to the current one is his hard-hit rate.

After posting a 60.7% hard-hit rate on fly balls last season, his current hard-hit rate on fly balls is 39.6%.

Upon looking at the rest of his quality of contact numbers in this situation, there hadn't been much change until this year. There's still plenty of time for him to make his 2017 numbers look more like what he's done in the past, but this is certainly less than ideal.

Since his quality of contact on both line drives and ground balls hasn't experienced the same downward trend, this clearly seems to be the root of the problem.

The Pitches He's Having the Most Trouble With

While Yelich's performance against certain pitches is mostly down across the board, there are two specific offerings that he's really struggled with this season: changeups and curveballs.

And if we compare some key statistics between 2016 and 2017, there are stark contrasts that jump off the page. The below table shows how his OPS, ISO, wRC+ and wOBA have changed against each offering.

Situation OPS ISO wOBA wRC+
vs. Changeups in 2016 .846 .257 .360 135
vs. Changeups in 2017 .532 .057 .241 54
vs. Curveballs in 2016 .841 .175 .361 136
vs. Curveballs in 2017 .552 .067 .250 60

This is never a good thing, especially when these are two of the four pitches he's seen the most often this season, according to FanGraphs.

There are quite a few positives to Yelich's performance up to this point -- after all, his 80.2% contact rate and 8.2% swinging-strike rate are on pace to be his best marks since 2014. The one thing that had been missing from his offensive game prior to 2016, though, was some more power.

He showed that he was able to find success in that department despite a batted-ball profile that's very light on fly balls because he maximized his production with the fly balls he hit. If the approach isn't going to change, he'll need to find a way to channel the 2016 version of himself to make it a reality again.