In fact the tricky part now is to figure out how to put this into practice in team building, in deciding where to position players (who should be in center field? etc.).
If you know now why a player from 1894 or 1923 or 1975 or 2008 is a C/B- at their position, how can you determine who will be better to use defensively between that player and another from another year with similar letter grades?
In general - and clicking on that link I used to compare Raines to the average for his season
http://www.baseball-reference.com/leagues/MLB/field.shtml
is a good starting point and demonstrates this - fielding has improved season after season in a linear way. Range is more complicated. It has gone UP in a linear way year after year since 1871. This is, I assume, due to increases in strikeouts, which reduce the number of putouts and assists in the field. The page I just linked to above shows that defensive chances (CH = putouts + assists + errors per 9 innings) has decreased per game from 47 in the 1870s to 37 today.
We know that 19th century fielders bring down defensive quality here, that being because a B for 1894 is not as good as a B for fielding in 2015. But how do we figure out who has more range - the 1894 player with a B or the 2015 player at the same position with a B range? Technically a B in 2015 should be inferior to a B in 1894, which involved more putouts, but I am sure that this is how it works nor how it should in practice. So here I will ask if anyone understands this part better than I do.
In putting together some fielding-based teams lately I have been relying on performance history - how many errors, how many + or - plays on average, though that is no guarantee of anything in the future. Ideas?
3/4/2016 4:00 AM (edited)