Wright has been having trouble in wet weather, and Pomeranz may show signs of getting tired with the jump in innings.But there is a zero chance the person who takes that spot will be Kopech and I would guess only a slightly above zero chance that Kopech gets a chance in the bullpen. If they want four starters and ERod isn't one of them they will use Price, Porcello, Wright and Pomeranz.
Even if the PitchF/X shows Kopech could be acceptable in MLB these guys aren't robots, no one is going to risk their job by bringing a guy up from A+ to start in the playoffs.
If Erod does continue to struggle, Kopech could get a couple starts in September, to test his performance.