Pitch location after the 2nd HR. It was all over the zone. Before that there was a pattern.
A At bat is a battle between the pitcher and the hitter. A pitcher normally will have a plan to attack the hitter. Normally they will go fastball up then work a curve down then go up again. A sinker/change up pitcher will stay down in the zone and play with speed and keep the location the same. Throw off the timing.
Keegan falls into the first type. He should be starting upper half of the strike zone with his tunnel. The curve will drop to the lower half for strikes. The fastball will stay upper 1/2 . Then he can go up the ladder to get hitters to chase. But it is up a ladder so start at the top then bring it up a few inches then again. Vs pop a fastball up there right off the bat. A hitter knows the zone. But inching him up will expand that zone. Another good mix in to do is while the hitters eyes are looking up in a sequence is to pound a fastball down on the outer edge and get a freeze. This only works when you have his attention up and you want to sneak a strike out. This will only work once in a while. It becomes a pattern then hitters will expect it.
Off topic,
I was looking at a cut video of Abbott's strike out. Something cough my attention. It was his pitching arm. He was opening up too much. This reminded me of a piece done on Giolito. When he first came up his back arm would be hanging back by his hip like Abbott's is. He adjusted to
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Abbott
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So Cory might need a tweak before becoming a full time starter. But the talent is there.