Quote: Originally posted by Ox on 10/13/2009Why does the league fielding percentage average of the batter and pitcher's season have any impact on how well a player fields? This would mean that a fielder would field better behind Roger Clemens than Walter Johnson. And if Ty Cobb came up to bat suddenly all of the fielders would be much worse than if Barry Bonds is batting. That doesn't seem to make any sense. Why isn't fielding just normalized based on the league average that year vs. historical average?And, even though this aspect doesn't make any logical sense to me, are pitchers and hitters going to be priced on their effect on the defense behind them or the opposing defense? Or else, there are going to be teams of deadball hitters and modern pitchers because they will be getting a free advantage by making the opposing fielders worse and their's better.
Good questions (ones we dealt with internally).
Comparing the fielder only to his league average doesn't do much because the player is already better/worse compared to the average. For instance, a .980 SS from a season with an average of .970 is already better than the average.
More inputs are needed to make it a true system. The batter and pitcher are the other inputs, even though it's odd to think they would be involved in the decision as to whether the fielder makes an error or not.
Try to think about it another way: the fielder is playing a game with players from different eras and all the eras have to be represented. A deadball pitcher currently suppresses homers because during his era there weren't many homers. But, his era had low fielding percentages. This system now reflects that. Spun the other way, pitchers today give up a bunch of homers but have good defense behind them. Throw Clemens on the mound with a bunch of 1890 fielders and he'll give up more homers but the defense will improve. It's meeting closer to the middle of all parties involved.
For the other question, there are pros and cons to these strategies. While you can pull the opposition down or your own defense up, it comes at a cost as you're also incurring the penalty.