Good article by Speier in the Globe , using several analytics, to discuss the problems of Sox starters after the A-S break . Fatigue is only one factor . Middle -middle pitches are a small factor. Pitching on the edges , and not inducing swing/misses with 2 strikes seems to be an issue. Umpire strict calls on very close pitches doesn't seem to be part of the issue , but they are inning changers.
Pivetta having to skip a turn is a bit surprising since he is not exactly a first time starter.
Grissom assigned to WooSox makes sense . He will get a turn on the 26 , I am sure, before season end.