Perhaps you have seen this before. I will use Taijuan Walker, Seattle pitcher, as an example. He was sailing along in his last start until his teammates had a long inning, scored only two runs, but the Kansas City pitcher threw a lot of pitches during the inning. And when walker takes the mound, he has no control, is out of sync, and gives up four runs. I saw it happen to King Felix as well, and many pitchers over the years.
Lets take close look at two innings. Seattle scored two in the 3rd in which there were three hits and a walk. Walker then pitches and has a quick 1-2-3 inning. Then in the fourth Seattle gets two runs, during which there were two hits, two walks, and a pitching change. Santana, Kansas City’s starter, lasted 3 and 1/3 innings, throwing 71 pitches, only 38 for strikes.
I think what happens is when a pitcher sits for too long the adrenalin empties, the energy flowing out of the pitchers arm into the ozone. The pitching muscles cool off and the competitive edge cools a bit as well. Nothing good comes from sitting 20 minutes. Walker simply was sitting too long during the third and fourth innings when his team was batting. He did have a 1-2-3 fifth that ended his night. He regained his pitching power because he threw so many pitches during the fourth when he gave up the four runs while facing eight batters. He got his rhythm and mojo back.
So what to do? How to refill the energy for a delicate pitcher?
When the pitchers team is still batting close to the twenty minute mark, then the pitcher should go beneath the stands where the batting cages are and run around, or play catch, or do jumping jacks. Do something to keep the energy flowing, keep the muscles tuned.
I have seen pitchers suddenly lose it too many times, especially in innings three though five, that there must is something to my theory. Perhaps if a Sabermetric member reads this, he will research and study in order to verify my theory.
In the meantime the next time a team has a long inning, see what happens when the long sitting pitcher regains the mound.