This tells me two things.
1. Kopech will be called up in June.
2. He will replace Lopez when he comes back. Unless Hamels is awful, in which case he becomes a lefty ace hopefully in the pen.
For anyone who thinks it's crazy to call up Kopech in June remember this we get that year back we lost, and he will pitch through the remainder of the season and for a playoff run. They will tell him they want him to ease back into things at AAA limiting innings pitched and increasing rest.