EDITOR'S NOTE: We're moving on to round two of our process seeking one or more new BCB contributors today with the second post from Eric Nehm. Eric's first post led off this project on January 4. - KL
At the start of last season, Brewers fans knew very little about Norichika Aoki. They knew that Aoki was a 30 year-old Japanese outfielder that the Brewers had signed to a two-year deal after posting 2.5 million dollars to negotiate with him, but little else beyond that. They knew that he may be able to give the Brewers some relief as Ryan Braun served a 50 game suspension, but it was difficult to project how successful he would be because it is impossible to know how a Japanese player's stats will translate in Major League Baseball.
One year later, Brewers fans know considerably more about Aoki. After Braun's suspension was overturned, it looked as though Aoki would be little more than a 5th outfielder for the Brewers, but as the season unfolded Aoki ended up becoming a crucial part of the Brewers' success. Aoki appeared in 151 games, starting in 119 of those games, and put up very respectable numbers. In 588 PA, Aoki posted a .288/.355/.433 line and recorded 150 hits, 81 runs, 50 RBI and 30 SB.
As always though, fans are looking forward and curious what Aoki will bring to the table next season. In an attempt to figure out how effective Aoki will be next season, I took a closer look at the possible problems Aoki could face in the upcoming season.
Fatigue as Everyday Starter
Throughout the season, Brewers manager Ron Roenicke spoke about the difficult Aoki may face adjusting to the daily grind of Major League Baseball. During late June, Roenicke even mentioned that fatigue as a reason for an Aoki slump. For Aoki, it wasn't just a lack of days off during the Brewers schedule, but also his refusal to take a day off and cut back on his swings.
Taking a look at Aoki's monthly splits, there may be reason for concern about fatigue playing a factor in his success this season. To start the season, Aoki was the Brewers' 5th outfielder and used primarily as a pinch hitter off the bench. After performing well as a pinch-hitter and occasional starter, Aoki became a regular starter in mid-May. As a starter, Aoki performed well in May and then started to struggle in June and July. In these two months, Aoki's Batting Average on Balls in Play (BAbip) dropped significantly to .278 in June and .279 in July from a robust .338 in May.
When most people discuss BAbip, they see it simply as a measurement of luck, but that is a short-sighted look at the statistic in my opinion. It is also necessarily to consider the quality of contact a batter makes with the balls he puts in play. This is especially important to remember while taking a look at Aoki's summer struggles. Though Aoki's batting average may have decreased, his on base percentage didn't really suffer. This would suggest that though Aoki was struggling swinging the bat, his approach at the plate was not suffering. Therefore, when dissecting Aoki's drop in BAbip, it was more likely that he was fatigued and not making great contact with the ball rather than simply going through a streak of bad luck. All of this makes Roenicke's management of Aoki's playing time that much more important in this upcoming season.
Unsustainable Infield Hits
Last season, Aoki led the entire league with 34 infield hits. A few commentators have suggested that this is a worrisome stat suggesting a sure sign of regression. Some believe that it's unlikely that Aoki will be able to collect this many infield hits this season, but I'm not so sure I agree.
Aoki is not necessarily the fastest guy in the league, but his batting stance and quick start out of the batter's box help him leg out an incredible amount of infield hits. Aoki will of course be another year older this season and will likely lose a little bit of his natural speed, but I would argue that this will not affect his ability to collect infield hits. Even if Aoki is a bit slower, his ability to quickly get out of the batter's box will likely prevent the amount of infield hits he collects decrease substantially this next season. Look no further than Ichiro Suzuki. I'm not saying that Aoki is as talented as Ichiro, but it would be silly to ignore Ichiro posting 30 infield hits last season at 38 years old when discussing Aoki's upcoming season.
Too Many Groundballs
Along with the infield hits, a few more extreme numbers really stick out when taking a closer look at Aoki's stats from last season. The first of these two numbers is his groundball percentage. Last season, Aoki hit the ball on the ground 55.4% of the time, which was the 8th highest percentage in all of baseball. Aoki coupled this high ground ball percentage (GB%) with the league's sixth lowest line drive percentage. Obviously, these two statistics go hand-in-hand, but both statistics still seem alarming for a 31-year old player.
To understand the regression that I should prepare for in the upcoming season, I decided to take a look at any season in which a player 30 years or older recorded a GB% of 55 or higher. In the last ten years, there have been 29 different instances in which this occurred. Here is the link for the complete data.
It is impossible to look at this graphic without mentioning the overwhelming presence of Derek Jeter and Ichiro Suzuki. Of the 29 listed seasons, Jeter was responsible for 8 of them, while Ichiro was responsible for 6. With the exception of Jeter's 2010 and Ichiro's 2011, both players were able to put together above-average season after above-average season while putting the ball on the ground at an extremely high level. Once again, I'm going to try to steer away from perennial All-Stars because I don't believe Aoki to be at that level. I just wanted to illustrate the point that it is possible to succeed consistently as this type of hitter. It just happens to be extremely rare.
(click the chart to enlarge)
Let's take a closer look at this rarity by eliminating Ichiro and Jeter. The remaining 15 occurrences were recorded by 11 different players. Of these 15 instances, only 2009 Luis Castillo (.302) and 2007 Luis Castillo (.301) were able to record batting averages above .300. Only Luis Castillo ('06,'07,'09), Darin Erstad (‘04), and Dave Roberts (‘06) were able to record a better AVG and OBP than Aoki recorded last season.
The players including in the graphic above were able to record only marginally better statistical seasons with BAbip numbers nearly .020 greater than Aoki this past season. In fact, of these 15 occurrences, Aoki posted the fourth worst BAbip at .304 and still managed to have one of the best seasons. If Aoki's BAbip does increase this season, which seems likely when looking at the high BAbip numbers this group of players recorded, Aoki may be able to become a .300 hitter for the Brewers and contribute even more than he did last season.
As I started to write this piece, I was convinced that putting together an argument suggesting a regression in Aoki's numbers would be simple, but then I actually took a closer look at the numbers. Every single link I opened made it more and more difficult to write a piece about his likely regression and ultimately made me abandon the piece all together to write a completely different piece.
So, while everyone else may be screaming REGRESSION, I would not be shocked if Aoki puts up better numbers this season with the Brewers. While league average BAbip this past season was .297, a majority of hitters that posted a GB% of 55 or higher also had a much higher BAbip, so an increase in Aoki's BAbip would not be out of the question and might actually be likely. The only real concern I have with Aoki would be the fatigue he may experience from being counted on to be the everyday right fielder. If Ron Roenicke is able to manage Aoki and get him the rest that he needs, there is no reason Aoki should not have a season just as good as last year, if not better.