"Obviously, you want to go over there," Zimmermann said. "I had all the plans and everything made up. I want to pitch in front of my family. Hopefully, everything is fine. [Not pitching in the All-Star Game] is not the main problem. It's getting healthy. Hopefully, there will be another one down the road."
The count was 2-2 to Phillies catcher Cameron Rupp when Zimmermann summoned Williams to the mound. Pitching coach Steve McCatty and athletic trainer Lee Kuntz also went to the hill to check on Zimmermann. About a minute later, Zimmermann was removed in favor of reliever Craig Stammen, who struck out Rupp on one pitch.
Zimmermann said he started to feel tightness in his arm an inning earlier and that the injury was getting worse with each pitch. After the game, Zimmermann said he felt OK but would have an MRI exam on his right arm.
"It was getting a little tight in the last inning, and every pitch, it was getting tighter and tighter," Zimmermann said. "It was cramping up. I didn't want to push it too far and have something worse happen. I figured it would be best if I came out. We are going to get an MRI and see. It's pretty much muscle in the middle of the biceps. I think it should be fine."
Zimmermann said he did not think the injury was related to his elbow. He had Tommy John surgery in 2009.
"My shoulder feels fine; my elbow feels great. I did all the test. Everything was good. Everything was strong. I'm not too worried that the biceps is ticked off right now. Hopefully, a couple of days off, it should be better."
It was not a good night for Zimmermann before the injury. Over 3 1/3 innings, he allowed four runs on six hits. The Phillies scored their first two runs in the second inning, when Domonic Brown doubled in Marlon Byrd and Cody Asche. An inning later, Jimmy Rollins hit a two-run homer to make it a 4-0 game.
"The command wasn't really there. I made a few mistakes," Zimmermann said. "They were jumping on the first-pitch fastball. … They were squaring me up pretty good."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.