Jordan Zimmermann is absolutely not horrible, not even bad. He's just a six-inning starter. You have to understand that.
Jordan couldn't walk the #8 hitter on his own. That's on Davey.
If Davey has him walk the #8 hitter than it's still a tie game. And a quality start with 6-7 IP every game will put you as one of the better pitchers in the league. All but the very elite pitchers go consistently deep in games. That's something you need to understand.