Woodruff grimaced after throwing a second strike to Diamondbacks leadoff hitter Tim Locasto in the fourth inning and Milwaukee's trainer immediately ran out with manager Craig Counsell.
After a brief discussion, Woodruff slowly walked to the dugout. Counsell said after the game Woodruff would have an MRI on Monday and will go to the 10-day injured list.
The hard-throwing right-hander allowed four runs on six hits. He was replaced Junior Guerra with the game tied 4-all.
Woodruff has been Milwaukee's best pitcher this season, earning his first NL All-Star nod. He entered Sunday's game 11-3 with a 3.53 ERA and had allowed three earned runs in 20 1/3 innings his previous three starts.
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