The coach is replacing the pitcher, I think.
I usually substitute yogurt for sour cream.
I can’t exchange this ring for money.
You know the kanji is substitute, and you know this is a verb. There are other similar ones, but this one means to replace. In order to remember that this particular word means "to replace" focus in on the え. You have an egg in your hands that you notice isn't any good (it's black and moldy). So, you replace it with another egg (or substitute it with another egg, or exchange it with another egg, etc).
The reading for this one is the same as 代わる which you learned in a previous level. As long as you know that one you should be able to learn this one's reading as well.