Friday, September 03, 2010

Should the Tigers Bring Back Peralta in 2011?

There has been much discussion on the internet about Jhonny Peralta’s potential role on the Tigers in 2011.  He has a club option that would pay him $7 million next year.  If they want him back, they can either allow the option to kick in or decline the option and try to sign him at a lower salary.  The other question is whether he would play third base or shortstop. 

With Brandon Inge’s contract coming to an end after this season, the Tigers could replace him with Peralta.  According to the Fan Graphs weighted runs created statistic (wRC or RC), Peralta has 57.7 RC in 506 Plate appearances (PA) this year.  Over 650 PA, that would be 74 RC.  Similarly, Inge’s 52.5 RC over 466 PA translates into 73 RC over a full season.    So, there is only a one run difference between the two.  Performing similar calculations on 2009 data yields 65 RC for Peralta and 70 RC for Inge.  So, based on the last two seasons, Peralta would not be an upgrade over Inge offensively. 

Defensively, I’ll look at the Ultimate Zone Rating (UZR) and Defensive Runs Saved (DRS) over 2009-2010 because it’s always a good idea to use multiple fielding measures and multiple years when evaluating defense.  Peralta had the following numbers at  in 2009-2010:

DRS –4 +2
UZR –2 –4

Averaging those together yields an estimate of 0 defensive runs saved.  Now for Inge:

DRS +8 -1
UZR +7 +3

That averages out to +4 runs saved.  So, I’ll estimate that Inge is 4 runs better than Peralta defensively.  Peralta is only one run better offensively this year, so he’s clearly not an upgrade overall.  They are probably better off with Inge at third for next year, but it’s not a big difference.

What about Peralta at shortstop.  Would you rather have Peralta or Ramon Santiago/Danny Worth?  Some of you might be thinking “none of the above”, but let’s look at those two options.  The table below looks at the runs created numbers for the three shortstops in 2010.

Player PA RC
Peralta 506 57.7
Santiago 334 34.6
Worth 115 9.7

We saw above that Peralta would have 74 RC over 650 PA.  Suppose, we give 400 PA to Santiago and 250 to Worth.  Their estimated RC are in the following Table

Player PA RC
Peralta 650 74
Santiago 400 42
Worth 250 21

Over a combined 650 PA, Santiago and Worth would  have 63 RC.  That is 11 runs fewer than Peralta.  Do Santiago and Worth make up for it defensively?  We are dealing with a lot of small sample sizes here, so I’ll go back five years.  First, Peralta:

DRS –6 –6 –2 –6 +5
UZR –6 –11 –12 –1 +3

That averages to –4 runs which Peralta cost his team.  Now, Santiago:

DRS +1 +8 –6 –2 +9
UZR +2 +3 0 –1 +6

That comes out to +2 runs saved on average.  The data on Worth is too limited, so I’ll assume that he is average defensively, which based on observation and reputation seems fair.  So, let’s say that Santiago/Worth are +1 defensively.  That makes them five runs better than Peralta.  Combine that with the offense and Peralta is six runs better.

My conclusion is that the 2009-2010 version of Peralta would not be an upgrade at third base, but would be a slight upgrade at shortstop assuming his defense does not fall off a cliff.  Now, if Peralta can get back to his 90 RC production of 2008, then he would be a big upgrade at either position. My original thought was that he would be ok at third but not at shortstop.  I'm still leery of the Tigers using a below average defender at shortstop and I hope they look elsewhere. However, it looks like shortstop might actually be a better idea than third base. 


  1. Lee,

    How does Peralta, over his career, perform against the Twins and the White Sox? I am thinking I have read elsewhere that he has good numbers against them.

    Point being if he is negative ## overall but is a positive force against the Twins and Sox I would probably take it.

  2. Sorry above question was by frm710

  3. .237/.305/.375 vs. Chicago
    .247/.310/.398 vs. Minnesota

    I think he has done well against those teams recently, but split stats usually even out over time.




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