Wednesday Rockpile: What can we expect from Wilin Rosario?


Editor's Note: The following post is a part of the 2013 Purple Row Writer Search -- our quest to find some great new contributors to Purple Row

If there's one position that has proven itself controversial around these parts over the years, it's catcher. But with the Great Catcher Wars of 2008-09 now several years in the past, the Rockies believe they have their catcher of the future (and present) in Wilin Rosario.

There's no question the Baby Bull provides some pop in the middle of the order, hitting 28 home runs with a .270/.312/.530 slash line and an OPS+ of 107. Not bad for a rookie whose ability to succeed in the majors was once uncertain. Factor in a BABIP of just .289 and there's little reason to think he can't match or exceed those numbers in 2013, making for a formidable CarGo/Tulo/Rosario trio in the heart of the order. (Insert caveats about health and whether CarGo and Tulo perform up to expectations here.)

The main thing that held Rosario back is something that has hurt the team for a few years now: fielding. Rosario certainly has the tools to become a competent fielder. Maybe even an above average one. The question is how much of a step he takes in that direction in his second full season in the majors. Fielding of course is notoriously difficult to quantify statistically, but let's try it anyway.

Note: While I'm trying to become more knowledgeable of sabermetrics I'm not nearly as good with them as many of our readers so there's a good chance I'll end up accidentally misinterpreting and/or misapplying metrics. Feel free to crush me for it in the comments.

No doubt as soon as he reports for Spring Training, we'll hear plenty of stories about how hard he's working on his defense and what great shape he's in. (You should see his new cutter!) Naturally, those stories will have to be taken with a grain of salt, but I do like the fact he's chosen to forgo the WBC in favor of being with the team. Certainly there could be something to be said for spending part of the spring playing alongside Miguel Olivo and Carlos Santana to see how those more veteran players handle their business, but isn't that what Ramon Hernandez is here for?

In 2012, Fangraphs had Rosario down for an abysmal -11.1 fielding runs above average, which I'll shorten to just call "fielding" in the rest of this post. Even after the positional adjustment, he still sits at -3.6. ZiPS projects him to improve to -3 in 2013.

This got me thinking if we can glean anything about his potential future performance based on catchers of Rockies past. I figured the best place to start would be with guys who primarily played the position and began their major league careers in Denver. After eliminating guys who only played one season or had a uselessly small number of innings behind the plate, I was down to just four names: Jayhawk Owens, JD Closser, Ben Petrick and Chris Iannetta.

Because I'm looking at change from their first full season to the next, I had to narrow the list further. Owens and Closser didn't play nearly the innings of Rosario in their longest seasons and the following ones were short enough to render the numbers basically worthless for my purposes. Petrick also had a decline in innings, exacerbated by the fact that he started playing a few other positions (and, as we now know, the early effects of Parkinson's). That leaves us with Doom.

In 2008, CDI played 837 innings at catcher (Rosario played 878 last year). During that season, he finished -3.2 in fielding, +4 after positional adjustment. In 2009, he played nearly 75 fewer innings, but improved his fielding number all the way to 2.4, 8.9 after adjustment. However, he's been up and down since then, oscillating between roughly -4 and +2 over the course of his career.

Of course, that's just one comparison. Let's look at the guy mentoring Rosario, Hernandez. In 2000 at age 24, Ramon caught 1,062 innings, finishing with a fielding rating of -2, 7.1 after adjustment. In 2001, it increased to 6 and peaked at 9 in 2002. This guy seems to know a thing or two about improving fielding as a young catcher. Of course, how much mentoring is worth is even harder to quantify, but assuming Wilin takes instruction well I think we can conservatively count it for a 1-2 point bump.

Note: Fangraphs fielding rating is based on UZR after 2002 and TZ before then, so it's not necessarily a direct comparison.

I figure if two comparisons is good, three is better so I also looked at who ZiPS compares Rosario to in 2013: John Buck. Buck's fielding value over his first three seasons in KC was very consistent, finishing at exactly zero for '04, '05 and '06. His value fell the following two years, bottoming out at -5.8 in 2008. He's since come back, putting up a 1.8 last year.

So what can we glean from these numbers? For starters, catchers' defensive value tends to fluctuate quite a lot from one season to another. But there does tend to be noticeable improvement in those first few seasons in the majors. I certainly don't expect Rosario to turn into Johnny Bench all of a sudden, but I do think we're going to see noticeable improvement in his defense over the next couple of years. With his offensive production, I expect him to be at least as valuable to this team in 2013 as Dexter Fowler was last year and hopefully before long will be regarded as a cornerstone of the franchise similar to how CarGo and Tulo are now.

Links and such

Not much Rockies related news, but former Rox first round pick Jamey Wright has signed a minor league deal with the Rays.

The Dodgers spend a lot of money because they are about to make a LOT of money.


Eat. Drink. Be Merry. But the above FanPost does not necessarily reflect the attitudes, opinions, or views of Purple Row's staff (unless, of course, it's written by the staff [and even then, it still might not]).

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