career FP of at least .960 and 7-9 points higher than career lgFP, and RF9R significantly above 1
League fielding percentages at the pitcher position soared from the low .900s throughout the 1890s to the .940s by 1903-4, and with few exceptions the career lgFP of veteran pitchers has remained between .940 and .960 ever since (as will be seen in figure 1).
This minimum FP threshold was chosen because it is near the historical high for career-averaged lgFP (see below).
Figure 1 illustrates the evolution of fielding by pitchers over time, by plotting career-averaged lgFP as a function of the midpoint of each pitcher's career.
Interestingly, the NL-AL differential in career-averaged lgRF9 during the early to mid twentieth century seems less obvious than in career-averaged lgFP.