The Milwaukee Brewers caught a nice surprise in 2012 when Norichika Aoki turned in a 2.9 fWAR season and ended up compiling 588 plate appearances in 151 games. There are a lot of nice elements in his numbers as we shall see. With only one year in the Major Leagues (in this country), can he repeat those numbers? Only ZiPS doesn't think so. All the other projection systems think he will improve further. Let's take a closer look and see which system is going to be correct..
First of all, ZiPS does not believe in Aoki's 2012 power numbers. For a fairly small guy, Aoki racked up 37 doubles, four triples and ten homers. His .433 slugging percentage and .144 ISO had to be a surprise. ZiPS isn't the only one who thinks his power numbers will slip. But ZiPS is the most aggressive in his projected fall. The only natural place to look is to see what Aoki did in Japan.
And the numbers in Japan show us that what he did in 2012 with power numbers for Milwaukee look sustainable. His number of doubles was right in line with his production in Japan and if anything, his ten homers were somewhat less than his normal Japan production. My conclusion then is that his ISO should remain in the same ballpark as what he did in 2012 with a possible chance of it being slightly higher.
But power is only a part of the OPS and wOBA categories. Aoki would need to maintain his batting average and on-base percentage. The one thing that helps Aoki is that he nearly always makes contact. He only swung and missed on 4.6% of the pitches he saw in 2012. That is a very low number. And his plate discipline seems stable as he swung at only 27% of pitches out of the strike zone. So he'll make contact and he should walk fifty or so times this season.
The type of contact he makes concerns me a bit. Aoki hits a lot of ground balls. In fact he hit exactly twice as many ground balls as he hit fly balls. Only fifteen players in the majors had a higher ground ball to fly ball ratio than Aoki did. And of those fifteen, none had a lower line drive percentage than Aoki. And yet, Aoki's batting average on ground balls (and BABIP, of course) was .290.
I'm not saying it is impossible to bat .290 on ground balls. Jeter and Suzuki have been making a living doing that for years. But it is not the norm. As I have stated here before, the league average for ground balls is .238. That is the norm. Jeter and Suzuki have beat the norm for years and years. Is Aoki one of those guys too? Time will tell.
I'm not quite sure what to make of Aoki in the outfield. The scouting reports are that Aoki has a weak arm. And yet, he had seven assists from right field last season. Right field seemed to be his best position in 2012 and the only one that garnered him positive numbers of the three outfield positions he played. But a weak armed right-fielder doesn't make sense unless he keeps throwing guys out, right? He is best in a corner position and is really not a center fielder. But his batting game is more like a center fielder or a second baseman type. So he really doesn't fit.
Norichika Aoki will be a big part of whether the Brewers compete in 2013 or not. If he has the kind of year he did in 2012 with his 30 steals in 38 attempts and his ability to get on base at a .350 or higher clip, he will aid that team's cause greatly. But if he cannot sustain his BABIP on ground balls, then he could fall down to the .260 and .270 range in batting average and that will drag off most of what he brought to the table last season. After weighing it all together, my conclusion is that Aoki is a regression candidate and is 31 years old. We'll have to see how it plays out for the Brewers.