I have been having similar problems with relievers after 20 pitches. The leftie was brought in because he had given up one hit in 12 innning on the month and was my most reliable relief pitcher on my staff, holding RHB to under .200 for the season.
I miss the pitcher's name changing colors to denote whether or not he is tired. Checking his profile after every batter is tedious, as is visiting the mound, especially since I always get the feeling when they say "I'm fine - just let me pitch" they get mad and lose their concentration. But that could just be me.