Matt Tolbert is playing out of his mind right now, and if you're the Twins, this is clearly a good thing. His play is even causing a groundswell among the fan base to make him the starter at shortstop and I think this is something that needs to be addressed. In one camp, you have people who like the fact that Tolbert should be a better offensive player over the course of the season. The other camp believes that Adam Everett can save as many or more runs with his glove. Let's break it down:
|Name||Lifetime AVG||Lifetime OBP||Lifetime SLG||AVG H||AVG BB||AVG TB||AVG 2B||AVG 3B||AVG HR||Runs Created|
So over the course of a season, Tolbert is good for an additional 19.35 runs. That's pretty significant. If you consider that the Twins averaged 4.43 runs per game last year, that's an additional 4.37 wins that Tolbert bring to the team. Of course, that also presumes that Tolbert can translate those minor-league numbers into major-league numbers. While it is far from impossible for him to do so, I think many would say the odds are against that given the traditional growth rates of players transition from the minor leagues to the major leagues.
Now is where things get a bit tricky and I'm prepared to admit that defensive statistics are not my forte, but using some pretty simple logic-based calculations, I think we can fairly easily translate Everett's effectiveness into a sort of reverse runs created. Let's say, runs prevented. Also, as a caveat to anyone who is interested in really understanding defensive metrics, PLEASE look into buying a copy of The Fielding Bible; its written by some of the greatest minds in sabermetrics and is a MUST for anyone who is interested in understanding precisely how defense impacts a game. Furthermore, even if you aren't going to buy the book, I strongly recommend reading the excerpts posted on their website.
The system they use is called +/-, and essentially, after charting every single ball put in play, they determine based on ball speed, location, vectoring, etc... how many more (or less) balls a player converts into an out than the average. Players who get to balls below the average receive negative ratings. Adam Everett led all shortstops in the major leagues from 2005-2007 with a +92 rating (Jason Bartlett was second with a +45.) While I'd love to use these stats, it's not possible since Matt Tolbert's numbers aren't available. So we need to find another way of doing this. Getting back to setting up our own system...
First, I'll be using The Hardball Times fielding stats. A basic fielding stats primer: ZR= Zone Rating BIZ= Balls in zone. Plays = # of balls in a players zone fielded (Plays/BIZ=UZR) OOZ= Outs made on balls out of a fielders zone. Since shortstops don't really have any effect on triple and homeruns, and only have a very small degree of effect doubles, I'm going to presume that every out that a fielder doesn't make, counts for a single. In order to ensure the closest approximations possible I'm going to use the data available from Everett's past 5 seasons. In Tolbert's case, I only have a sample size of nineteen innings. Clearly this presents a major statistical dilemma, but I can only work with the information available to me.
As a precursor, I'll be using an average total balls in zone for the shortstop position over a 162 game season of 420. That will effect a players AVG Plays as well as thier AVG OOZ plays. Obviously the last shortstop to play 162 games in a season was Miguel Tejada (and before him Cal Ripken Jr) but guys who do are rare. And neither Everett nor Tolbert will do so. But it gives us an important baseline to work from.
|Name||AVG BIZ||AVG Plays (420*ZR)||AVG OOZ||Total|
|Everett||420||369.60 (.880)||77.90||447.50 (448)|
|Tolbert||420||326.76 (.778)||¹37.00||363.76 (364)|
¹: Brendan Harris' 2007, a player I think Tolbert compares well to. I had to make an arbitrary decision since Tolbert has yet to record an out from outside of his zone. Harris created one out of zone out per 20.29 innings last year. Tolbert having played 19 innings and not yet made an OOZ play was the nearest comparison given Tolbert HAVING made an OOZ play.
This shows us that Everett creates 84 more outs over the course of a season than Tolbert. Given that there are 27 outs per game you COULD say that means Everett's glove wins 3.11 more games per year than Tolbert's.
But now we need to plug this into 2007 hitting data. Last year the average major-league hitter batted .268/.336/.422. Over a 550 at-bat season that comes to 147 hits, 185 times on base (H+BB). Therefore, the average batter would've had ~38 BB. A .422 SLG works out to 232 total bases. If Everett prevents 84 more outs per season, that means he prevents 84/9 (9.33) outs (# of additional out/batters = Individual batters share of additional outs created) per batter.
Plugged into the same basic RC formula we used above, this "standard" hitter who had been averaging a RC of 72.99 would now be averaging an RC of 66.75. Now, since Everett's defense is in play over 9 batter over the course of a season, that negative variation of 6.24 becomes multiplied by 9 to equate to 56.16.
Everett has a 56.16 Runs Prevented rating over Matt Tolbert. That would equate to 12.54 wins given the Twins average allowed runs of 4.48 per game.
Of course so much of this is speculative. We don't know if Tolbert can duplicate his minor league numbers and my study of the fielding stats is wildly simplistic. But I think the study is fairly accurate, and I'd be happy to discuss it with anyone who might be interested. The final results show that Tolbert's 4.37 additional wins due to his bat (over Everett's) do not make up for Everett's additional 6.24 wins from his glove over Tolbert's.