PHOENIX -- Milwaukee Brewers All-Star right-hander Brandon Woodruff has left his start against the Arizona Diamondbacks in the fourth inning with an abdominal injury.

Woodruff grimaced after throwing a second strike to Diamondbacks leadoff hitter Tim Locastro on Sunday, and Milwaukee's trainer immediately ran out with manager Craig Counsell.

After a brief discussion, Woodruff slowly walked to the dugout. The team said he left with "abdominal discomfort."

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.