Angels' Shoemaker to undergo MRI amid rib-cage discomfort

Though the Los Angeles Angels clinched a postseason berth with Monday's 8-1 victory over the Seattle Mariners, a possible injury to their de facto ace might curb their enthusiasm as the regular season winds down.

Matt Shoemaker, one of the American League's best pitchers since the All-Star break, left Monday's start after 96 pitches with "a little side discomfort" on the left side of his rib cage and will undergo an MRI on Tuesday, MLB.com reports.

"You're always concerned, and we're concerned when something like that happens to our pitcher," Angels manager Mike Scioscia said. "Sometimes it's a cramp and these guys bounce right back, and sometimes there's issues with an oblique that keep guys out for a long time. We don't know what the range is right now."

Shoemaker drew the attention of the team's medical staff in the eighth inning as he tried to loosen up his left side, resulting in his removal from the contest. The Angels can ill afford another injury to their rotation, which is already beset by the absence of Garrett Richards and Tyler Skaggs.

"Lot of things go through your mind," center fielder Mike Trout said. "He's been big for us this year. I talked to him. It's nothing too serious, I hope. He pitched great. Seeing the trainer go out there, you hope it's something small."

Shoemaker, who owns a 1.87 ERA with a 6.89 strikeout-to-walk ratio over his last 12 outings, refused to speculate about whether he'll make his next start.

"You always plan on doing that," Shoemaker said. "You can't speculate on anything right now. We'll find out more tomorrow."