Miami Marlins rookies Christian Yelich, Jake Marisnick: Expectations and reality

The Miami Marlins decided to answer their offensive woes midseason by demoting two rookies and replacing them with two others. Rookies Marcell Ozuna and Derek Dietrich were sent to the disabled list and to Double-A respectively, and the Marlins promoted highly touted outfield prospects Christian Yelich and Jake Marisnick. Marlins fans got a chance to dream about these players, as both were having fantastic, if injury-prone, Double-A seasons. Imagine what they could do for the Fish in the big leagues.

Flash forward to September, and it should not surprise you that neither of the two have reached lofty status yet. Yelich is still a starting player and likely has a hold on a job going forward, but Marisnick is lingering on the bench after a struggling start to his big league career. But what could we, as Marlins fans, have expected? These are rookie players, and even though Christian Yelich was considered an elite prospect, not every rookie jumps ahead like Jose Fernandez did in 2013.

So let's look at these two players when they were first brought up and see whether they matched the expectations we had for them.

Christian Yelich

In reviewing Yelich's 2013 season in Double-A Jacksonville, our own Conor Dorney had this to say.

Despite all of Yelich's injury problems this season, he's still managed to post an impressive slash line of .279/.359/.504 with seven home runs. The fact that he's been able to display plenty of power in an injury-riddled season is especially encouraging and now he'll get a chance to display it at the big league level. There will likely be some talk about Yelich's increasing strikeout totals but I think it's fair to say that it's likely due to the injuries and having to "start over" twice already this season. If last week's Futures Game performance at Citi Field (2-for-2 with a double) is any indication, Yelich seems to be locked in at the plate and there's no better way to test that theory than at the big league level.

This encapsulates the good and the bad of Yelich's Jacksonville stint. The batting line was fantastic, and the power was a pleasant surprise for a hitter who is 21 years old and could be turning line drive power into home run power any minute now. Then again, the strikeouts to which Conor Dorney is referring did indeed go up as he faced more difficult competition, and there was newfound concern that those strikeouts would only get worse as the level increased.

Fast forward 190-plus plate appearances into Yelich's Major League career, and many of these assumptions have panned out. The strikeouts have been an issue at this level as well, as Yelich has whiffed in 21.2 percent of plate appearances. His advanced plate approach, however, has also earned him some walks, as he has walked in a more-than-respectable 9.4 percent of those plate appearances. He also has done this at the top of the lineup and primarily from the leadoff spot, where getting on base via the walk is at its highest value. While the strikeouts remain a concern, at least his plate discipline has turned out more or less as expected.

The thing that we have not yet seen in the bigs is the power that he flashed in Double-A. So far in the majors, he has an ISO of .109 and just three home runs hit thus far. Yelich has classic power "to the gaps," but thus far he has hit a double or triple in just 4.8 percent of plate appearances (7.0 percent of balls in play).

Currently, he is profiling a little as a singles hitter, and he has gotten away with it because of a high .367 BABIP. Now, in the minors he boasted a .380 BABIP for his career, so it is expected that he would hitter better than the average in the majors, but this is also quite high and unlikely to stick around. That power Yelich promised this season will have to kick in to help offset some of the singles he will likely lose.

Jake Marisnick

The Marlins had to be happy to see Marisnick dominate Double-A so thoroughly after struggling in the second half of last season. He flashed the power that his tools suggest he has, and he returned to the levels he saw in 2011 in Low-A for the Toronto Blue Jays.

Fish Stripes's own Sam Evans mentioned how Marisnick's season was fantastic enough to earn a promotion.

One can easily make the case that, in his 67 games for Jacksonville in 2013, Jake Marisnick was the the most valuable position player, not just on his team, but in the entire Southern League. Marisnick, who is 22-years-old, hit .294/.358/.502 with 12 home runs and 11 stolen bases in 298 plate appearances. Couple this with his outstanding defense and Marisnick is the biggest reason why Jacksonville managed to play above .500 ball even without Christian Yelich for a few weeks. In 2012, Marisnick really struggled with Toronto's Double-A New Hampshire in 55 games, hitting to the tune of only a 70 wRC+. Fortunately, due to his tremendous athleticism and a few changes he has made to his swing, Marisnick has more than doubled that wRC+ and has regained his place as one of the top center field prospects in the minors. No matter how you look at, Jake Marisnick's season has been nothing short of phenomenal to this point.

The defense Marisnick provides in center field is a linchpin for his success in the majors, and so far, in a small sample, it seems like the defensive metrics like his play out there. Marisnick is a fantastic athlete, so it makes center field a natural fit for him. Given the Marlins' needs for a strong defensive presence in an expansive outfield, his performance so far has been a good start.

It is a good thing that he has performed this well in the outfield, because his work at the plate has been disastrous. He has almost undoubtedly been plagued by some bad luck (.234 BABIP), but Marisnick's primary issues in plate discipline still have not resolved. Even this year in Double-A, his numbers left something to be desired; he walked in just 5.8 percent of plate appearances and struck out in 22.8 percent of them. That has smoothly transitioned to the majors, as he has whiffed in 22.5 percent of plate appearances in the bigs while walking in just 5.4 percent.

Marisnick is offering up swings and almost everything, as he has a 52 percent swing rate. That is not limited to pitches in the zone, though his rate of 69 percent is high, but also to those out of the zone. Marisnick has swung at 34 percent of pitches out of the zone. Through the magic of his athleticism, he has somehow maintained an average-ish 80 percent contact rate even with all of those extra, unnecessary swings, but pitchers should eventually be able to exploit him.

Both Yelich and Marisnick have work to do with regards to improving their play in the majors. Yelich is closer to being ready for a full-time gig, and a solid month of September will all but assure him a role in next season's starting lineup. For Marisnick, the fact that he has languished on the bench for the past two weeks shows that Miami feels he is not ready, so do not be surprised to see him in the minors next year.

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