On a team of slumping players, Eric Hosmer has been one of the bright spots. As of this writing, his 159 wRC+ would be a career best by far. Hoz is hitting .333 / .383 / .525. Pretty good. Can it last?
Let's not get too worked up over this. We have about a month of data, and Hosmer has hit just as well or better in other months in his career. Focus not on the results but on the underlying peripherals. The underlying peripherals are bad.
Hosmer currently has a 61.7 percent ground ball rate. We have generally accepted that for starting pitchers, generating lots of ground balls is a good thing. Ground balls do not go over the fence. The same thing applies to hitters. Hosmer is not Ichiro up there slapping out infield hits left and right. He's a slugger pounding worm burners into the dirt. He needs to elevate the ball. He is not.
That 61.7 rate would also be a career high. While Hosmer does hit a lot of grounders for a first baseman (usually 50%+), this is unprecedented for him. There's not a qualified starting pitcher in baseball with a ground ball rate higher than Hosmer's. Noted ground ball specialists Dallas Keuchel and Felix Hernandez are in the mid-50s.
However, when Hosmer has managed to get the ball in the air for a fly ball, it's left the yard at a 20 percent rate. That would also be a career high. When the ball stays in the yard, Hosmer's getting a hit about 37 percent of the time (.367 BABIP). That would suggest either random variation or better contact. Hosmer's hard-hit rate has not increased, so my guess is random variation.
Noticing a pattern here? There are a lot of wonky underlying peripherals that suggest regression is coming. While his BABIP should come down, he should also elevate the ball a bit more to take advantage of his power. Those things will offset a bit, but the question is how much.
One good underlying peripheral (or peripherals, really) is his plate discipline. All those things look pretty good for the first month of competition. He is swinging less at pitches outside the zone, swinging at more pitches inside the zone, making more contact with pitches in the zone, etc. All those plate discipline things are in the right direction compared to last year.
So far, Hosmer is having a career year. There are some troubling underlying indicators, but things will probably even out such that he will hang around or be better than last year's performance. An important factor here is that Hosmer is 26. He's entering a pretty common age range to have offensive breakouts. It most certainly would not be unprecedented if the breakout continued.