Felix Hernandez was set to return to Seattle to have a stiff right shoulder checked by Mariners doctors after he lasted only two innings in his start Tuesday night.
Hernandez allowed four runs and six hits in the appearance.
There was no injury announcement after he was removed from the game, but afterward, Scott Servais said the right-hander was dealing with stiffness.
"He had some stiffness in his shoulder going out for the second inning, but there wasn't any pain," Servais said. "He said it was more like a dead arm, but there's obviously some concern when you are talking about a pitcher's shoulder. He's been a horse for us, but we have to get this checked out."
Hernandez has made at least 30 starts for the Mariners every season from 2006 through 2015.
"We should know a lot more in a couple days," Servais said. "At this point, it's just a dead arm."