The guy who led the majors in ERA just a few starts ago proceeded to give up eight runs over his next 2 2/3 innings of work.
Zimmermann was pulled after just 3 2/3, making this by far his shortest outing of the season.
It was also by far his worst. He allowed eight runs on eight hits, walked one and hit two batters.
The Nationals now trail 8-6 as we go to the middle of the fourth.
Zimmermann surrendered two two-run homers, one to David Freese in the second and one to Matt Holliday in the third. He then hit two batters in the fourth and served up a three-run double to Matt Carpenter, a blast which gave the Cardinals their first lead of this series.
Over his first 21 starts of the season, Zimmermann didn't have an outing shorter than six innings. In that time, he pitched to a 2.28 ERA and held the opposition to a .238 batting average.
Zimmermann was named the National League Pitcher of the Month for July after going 4-0 with a 0.97 ERA in six games.
In his last six starts, however, Zimmermann has only once gone six full innings. He has pitched to a 6.23 ERA and is allowing opposing hitters to bat .290.
Zimmerman just reached a career-high for innings pitched today, so it's possible that he's feeling a little fatigue in his arm. It's also possible that the shoulder issue which popped up a handful of weeks ago is still affecting his performance, although Zimmermann has denied that the shoulder stiffness is still a factor.
There's some time for Zimmermann to get things figured out, but he certainly isn't trending in the right direction as the regular season starts to wind down and the postseason approaches.