But more often than not, wouldn't pitchers 11-15 be of lesser quality than pitchers 1-10? Injuries obviously would dictate how many BP pitchers are used. But for example, Perkins will pitch about 65 innings no matter if the entire bullpen pitches 400 or 500 innings. So the pitchers accounting for the additional 100 IP from the bullpen are going to be of lesser quality and with it the stats will take a hit. I am not arguing that pens get tired, but more that fact that the more IP the bullpen pitches, those innings will be given to lesser RP's. I would think that some improvement from the SP (more IP) would correlate an improvement in the BP.