Has Mitch Keller become the worst pitcher in the Pirates rotation?

Donny Football in for the guys today! Mitch Keller had another terrible outing last night, and Donny wonders what’s next for him. Keller isn’t going deep into games and Donny says that’s a problem. Is he the worst starter in the rotation? How much of an issue is the Pirates pitching currently? It appears that their pitching has gotten worse from last year.