He's been out since April 25 with a bulging disk in his back.
"We'll see how he rebounds," manager Ned Yost said. "Generally if you're going to feel something, it'll be the next day or two. We'll throw him on the side, probably Saturday, and see."
Could Chen fit into the bullpen as a long man, something the Royals haven't had of late?
"He could," Yost said. "We haven't really needed one. It's nice to have it, though, when you do need it."
Third baseman Danny Valencia is rehabbing from a left hand strain with Omaha, going 3-for-8 with a home run in his two games.
"He's doing OK," Yost said. "It's just more getting at-bats and making sure his hand feels strong enough to compete."
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.