Replacement Hitting, Fielding
January 13, 2005
Yes, there is a difference. I think.
I was asked by one of my plethora of fans to look at the difference between hitting and fielding among replacement players. At first, I resisted the request (Go away! Bad request!) because you really can’t choose one or the other. When you have to replace a player, you can’t choose the batting skills of one guy and the fielding skills of another. You have to decide on one guy. And the reason I like Win Shares is because they combine the two skills into one number.
The other issue is that Win Shares itself is not the best metric for doing this sort of thing. As noted in the comments to my original post about Win Shares Replacement Level, Win Shares does not adequately account for the true differences between fielders. Bill James moderated the impact of fielding Win Shares, because he really didn’t trust them enough (my interpretation). As a result, there isn’t as much of a difference between great fielders and bad fielders as there should be.
The other issue is that Win Shares does not do a good job of differentiating between fielders on the same team. Fielding Win Shares are a “top down” calculation; for each team, each position has fielding credit given to it, and then that credit is split between the individuals who played that position. This makes fielders on the same team look similar, because the final step (allocating to individual fielders) is really based on playing time more than anything else. This is particularly problematic when considering the issue of Replacement Levels.
However, my fan insisted, so I relent. I have constructed the following two tables that show the ratio of batting and fielding Win Shares to the expected number of Win Shares in total. By themselves, these numbers don’t mean very much. But compared to each other, they give you a sense of the difference in different types of skills between regulars and replacement players.
I apologize that this analysis is so complicated, but I couldn’t think of any other way to easily show the difference between batting and fielding.
Batting Win Shares/Exp WS
Position Reg Rep Ratio
Catcher 0.64 0.31 207%
First Base 1.11 0.72 155%
Second Base 0.77 0.45 169%
Shortstop 0.68 0.31 220%
Third Base 0.85 0.41 206%
Outfield 0.99 0.65 154%
Fielding Win Shares/Exp WS
Position Reg Rep Ratio
Catcher 0.43 0.39 111%
First Base 0.12 0.11 109%
Second Base 0.34 0.31 112%
Shortstop 0.37 0.34 110%
Third Base 0.24 0.26 94%
Outfield 0.22 0.20 110%
As you can see, there is a big difference between regular players and replacement players in batting, and not a lot of difference in fielding. In fact, replacement third basemen appear to be relatively better fielders than the regulars.
I don’t know if this is a reflection of reality, or an inappropriate use of Win Shares. So I wouldn’t put too much stock in it. But I think it is safe to say that batting is what separates the regulars from the replacements.
Studes:
Pretty interesting. This would suggest that replacement players are lg-average fielders (10% worse than “regulars”), but earn about 50% of avg hitting WS (which means they create runs at about a 75% rate). All of that sounds reasonable.
As you say, WS may not be exactly the right tool for determining the relative off/def abilities of repl players. But at a minimum, doesn’t this suggest a major problem with the WS system? If WS is measuring fielding accurately, and avg fielders are no better than repl’s, then why give 17% of WS to fielders? In what sense is it meaningul to credit them with preventing one-third of the marginal RA? Alternatively, if WS is failing to measure large fielding differences between replacements and regulars, then that’s a big problem too (but personally I think it’s the former).
Posted by Guy on 01/14 at 09:27 PM
I agree that this suggests a major problem with the WS fielding system. I spent a lot of time working with Charlie Saeger on this issue last year. Here is a review of the different systems we played with:
http://www.baseballgraphs.com/blog/more.php?id=A69_0_1_0_M
Posted by
studes on 01/15 at 12:56 PM
Great post, just a couple quick things. I’m not sure if my Win Shares comprehension level is high enough, but it seems to me that the real problem isn’t with WS here, but with the concept of fielding replacement level. You say that “batting is what separates the regulars from the replacements,” and I don’t know how many people could disagree. Looking at it more generally, however, the methods we use to look at replacement players don’t have any connection to looking at replacement level fielders. On the one side you have Niefi Perez and Tony Womack, and on the other Frank Thomas and Gary Sheffield. FT and Shef would have to be even worse than they are now for them to lose their job at the major league level, esp. with the DH, but a little drop in fielding skill would send Neifi down to Iowa.
Posted by .(JavaScript must be enabled to view this email address) on 01/15 at 10:13 PM
Page 1 of 1 pages
Commenting is not available in this channel entry.
