2012 Preview: Cubs Middle Infield

As we all eagerly await the start of spring training, I thought it would be fun to put together some player previews. I initially thought about constructing player projections, but quickly realized that there are other projections that are far better than anything I could produce, and that we're all probably projectioned-out by now anyway. That said, I figured I'd address one meaningful question regarding each Cubs player in advance of this upcoming season. I start with the middle of the infield, (including catcher).

Catcher: Geovany Soto | Soto's 2009 season was hampered by a low BABIP, was this what plagued him in 2011 too?

In 2009, Soto posted a .246 BABIP - the 13th lowest in the majors - well below the league average BABIP of .299. As we can see from the chart below, the slope of his BABIP decline from '08 to '09 is steeper than the slope of his wOBA decline during the same period of time. This indicates that while his BABIP fell, his wOBA didn't fall as much as his BABIP might indicate.

On the other hand, in 2011, Soto posted a .280 BABIP - only slightly below the league average .295 BABIP. Flip back to the chart and we now see that the slope of the BABIP is less steep than the slope of the wOBA indicating that wOBA fell by more than what BABIP would suggest. What's the most likely explanation? Enter BB% and K%.

In 2009, Soto's walk and strikeout rates both improved, which is likely part of the reason that his wOBA didn't fall by as much as his BABIP suggested it would. In 2011, however, both Soto's walk and strikeout rates went in the wrong direction: he posted a career low walk rate and a career high strikeout rate. These two developments are likely why his wOBA fell by more than his BABIP suggested it would. While his 2009 season was likely a result of bad luck, his 2011 season was likely a result of his declining skills. Before you bring up his age, take a look at the following chart.*

The blue curve consists of all players. The red curve consists of 70 players since 1981 who spent at least four seasons with a minimum of 800 inning per season at the catcher position. The yellow curve consist of players who spent at least one season as a part time catcher since 1981.

Looking at the red curve, we see that catchers usually peak at the age of 26 and 27, and then begin declining at a rate similar to the all players sample. It's definitely possible that, at the age of 29, Soto is in his decline phase.

In the event that his BABIP climbs closer to his career average of .303 in 2012, I wouldn't be surprised to see Theo & Jed trade him at the deadline. Soto's not getting any younger, and a team desperate for offense may be willing to overpay come July.

Second Base: Darwin Barney | Did Barney run out of steam near the end of the season?

Below is a chart of Barney's 2011 cumulative wOBA on a daily basis.

While Barney's wOBA was between .320 and .340 for most of the first quarter of the season, it fell below .300 mid-season. While he managed to pick it back up to about .310 soon after coming back from his time on the disabled list, he ended the season with a .293 wOBA. Which version is the true Barney: the .330 hitter who just ran out of steam, or the .293 hitter who played above his true talent level early on in the season?

Research says the .293 wOBA hitter.* Statistics such as OBP, SLG, and OPS have been shown to stabilize after 500 plate appearances. Since wOBA is an extension of these statistics, we can expect it to stabilize and be a reliable indicator of true talent level after 500 plate appearances. Looking at Starlin's 2011 cumulative wOBA chart, we can see his wOBA stabilize almost as soon as hits 500 plate appearances.

Looking back at Barney's wOBA chart, we see his wOBA hovering between .290 and .300 after 500 plate appearances, suggesting that his true talent level is likely closer to his sub-.300 wOBA than the .330 wOBA he displayed at the beginning of the season. Here's to hoping I'm wrong.

Shortstop: Starlin Castro | How has his ability to hit for power developed since he broke into the majors?

The offensive numbers Castro put up in his age 21 season were phenomenal, and while there's much to appreciate, I'm sure that many of us are interested in the development of his ability to hit for power. Below is a chart of Castro's career cumulative ISO on the basis of plate appearances, (the first 506 plate appearances are from 2010, with the following 715 plate appearance occurring in 2011).

Once again, using research on the stabilization of statistics, ISO tends to stabilize at 550 plate appearances. If we look at Castro's ISO at 550 career plate appearances, we see that it's at around .110. By the end of the 2011 season, Castro's career ISO was much closer to .120, constantly hovering between .118 and .120. While Castro's ISO has clearly improved, his improvement might become even more apparent when we take a closer look.

If we compare Castro's two seasons, the increased power is much more apparent. If we look at Castro's 2010 ISO, we see that it stabilizes at .108. In 2011, Castro's ISO stabilized at .125 - a 17 point increase over the course of a season, which is tied for the 22nd highest positive ISO change of last season, (among batters with over 550 PA). Castro's 2012 ISO rates will show us if these gains are permanent and whether or not he can continue to build upon his power improvements.

Look out for a preview of the rest of the 25-man roster - or as much of it as I can get to - over the course of the next few weeks. In the meantime, let me me know (i) what you think of these three questions, and (ii) if you have any question suggestions for the rest of the 25-man roster.


* Thanks to FanGraphs for the catcher aging curve.

* Thanks to Pizza Cutter for his research on stabilization of statistics.

This is a FanPost and does not necessarily reflect the views of SB Nation or Al Yellon, managing editor (unless it's a FanPost posted by Al). FanPost opinions are valued expressions of opinion by passionate and knowledgeable baseball fans.

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