With the arrival of Mike Moustakas to the majors, Kansas City has both halves of their prized infield prospects up with the big club, the other being first baseman Eric Hosmer. While it is still way too soon to accurately conclude that either player will be a bona fide major league star, the initial returns certainly match the pedigree.
For Eric Hosmer, in a decent sample he has proven himself to be a fairly impressive rookie hitter. Currently, he boasts an .888 OPS in 156 plate appearances with the Royals. Impressive but not entirely surprising since Hosmer absolutely crushed minor league pitching over the last year and change, hitting well over .300 with great power.
In my opinion Hosmer was/is as close to a sure thing for quality major league production as you can get. After a slow start to his minor league career, Hosmer really took off after his corrective eye surgery. You can certainly look at Hosmer and see an athletic frame, decent speed, and a very appealing swing, but the story is really in his statistics. Hosmer had a decent K rate in his early minor league career, but it’s no coincidence that his success followed with a dramatic decrease in his strikeouts. His K rate went from about 23% K/AB all the way down to 12%; an absurd number for anybody let alone a power hitting 1b. Hosmer maintained an excellent rate of contact while belting over 40 doubles and 20 HR in his last full minor league season. As such, Hosmer is one of those rare prospects that combines very good power with excellent contact skills. Hosmer has struck out about 18% of the time so far in the majors (again using K/AB). Nobody should be all that surprised by the increase going from minor league pitching to the majors, but that rate is still amazing for a guy who features the kind of power (and future increased power potential) that Hosmer possesses. For some perspective, current star major league 1b such as Adrian Gonzalez, Mark Teixeira and Miguel Cabrera all feature K rates around 20% for their careers (although Cabrera has displayed a downward trend to about 16% in recent years).
Where Hosmer still falls slightly short of other AL 1b stars is in the area of walk rate and power. All three of the aforementioned 1b walk around 11% (BB/PA) for their careers (again Cabrera showing an increase to 13-16% recently). Similarly all three hitters maintain wOBA’s around .400 and ISO’s in the .250 range give or take. Hosmer has a walk rate of about 6.4% in the majors this year and was 7.1% in his last full year in the minors. Further, Hosmer’s ISO so far this season is only .166.
Hosmer’s K rate and minor league track record indicate that he is most definitely a 1b who can probably maintain a major league batting average in the .280+ range, maybe even .300+ ala his teammate Billy Butler. However, like Butler did early in his career, Hosmer does not yet walk enough to vault him immediately into an elite grouping of 1b hitters. Further, Hosmer, like Butler yet again, has not yet shown the kind of power (though ISO is still a long way from stabilizing yet) to put him in the elite category.
Before he was called up, I had stated that I thought Hosmer’s low end in the majors was that of his now teammate Billy Butler, a very good hitter, and that his ceiling might be as high as Miguel Cabrera from the left side, which would be absolutely fantastic for the Royals. The good news is, I think he’s already matched his low end as you can see by the similar numbers between Hosmer and Butler’s first few seasons.
The interesting thing now will be how he continues to develop. One would expect the walk rate and power to both increase, however that does not always happen. One or the other could stall out, in Butler’s case, to this point it has been the power that has not fully developed though he has managed to dramatically increase his walk rate. This is a bit counter intuitive because conventional thinking is that the walks are a bit less likely to increase dramatically than is power. In that sense, Butler is a bit of an oddball, but he himself is still young and could easily break out in that department as well, vaulting him close to Miguel Cabrera status. No matter which path Hosmer takes, I would at the very least expect some future development in both categories enough to push him close to an elite level. He is really not that far off already. This much is clear; the Royals have a fantastic new first baseman.
Projecting Mike Moustakas at this point is a bit tougher to do. However, similarly, there is a lot to like about “Moose”. The biggest standout in his game is the power. He put that on display in only his second game with the Royals, going deep for his first major league home run. There's no question Moustakas can really mash the ball to the tune of 36 home runs across two levels last season in the minors along with 41 doubles. In fact, it wouldn’t be a stretch to say Moustakas has more developed power at the moment than Hosmer. There are concerns about his ability to make consistent contact, however I am probably more optimistic than others. Usually, I do not find much to be concerned about for the contact rate of a prospect until they start to K more than 20% of the time in the minors. A big time power hitter like Moustakas could still feasibly strike out 25% of his AB in the majors and be a very effective player despite a lower batting average. That said, Moustakas has had a K rate well below 20% since his rookie year in the minor leagues and as such, I do not think making contact will be an enormous problem for him in the major leagues. For some perspective Evan Longoria’s minor league K rate was just below 20% K/AB.
Moustakas’s issues are really limited to walks and defense. In similar fashion to Hosmer, Moustakas has not walked at a high clip against minor league pitching, roughly 6% on BB/PA his last two full seasons in the minors. The development in the ability to draw walks can often be a slow moving process for major league players if it happens at all. Keeping with my Evan Longoria comparison, Longoria walked well over 2x as much as Moustakas in the minors. That plate discipline can manifest at the MLB level not only as a lower OBP but perhaps in a tougher time translating a K rate from the minors to the majors. Increased strike outs lead to a lower BA which leads to an even lower OBP. It can be a vicious cycle for a newly promoted minor leaguer. However, I still believe 25% K/AB is really still a worst case scenario for Moustakas because his contact rate to this point has been so good in the minors.
Moustakas’s defense has been graded as serviceable but not spectacular. However, that’s really not a concern so much as an indication he will never quite be an Evan Longoria or Ryan Zimmerman on the defensive side of the ball. Overall, it’s not enough of a concern regarding his positioning at 3b because he does not figure to move to corner outfield at any point.
Overall, I think some of the concerns regarding Moustakas are a bit overstated. Generally, specific problems such as lack of plate discipline will only be magnified at the major league level. For certain players, the difference between the majors and minors is enormous (think Brandon Wood). However, Moustakas is working from such a high bar of excellence in the minors with regard to his peripheral stats it is really hard to imagine him falling that far. I really think Moustakas low end is something like Adrian Beltre with more K’s and vastly inferior defense. Basically a middle to middle lower tier 3b at absolute worst. Best case scenario is probably David Wright or Ryan Zimmerman with inferior defense. Maybe Aaron Hill during his best season would be a good comparison due to the similar BB rates. Really there’s nobody at third who compares well with Moose so it will be interesting to see which path he will take as a player.
With two top prospects already here and many more very good prospects yet to arrive, the future is bright in Kansas City.