"We'll know more in the morning," Yost said.
But Yost did concede that it was likely Dyson would miss at least two weeks.
Dyson grounded out to second base in the second inning and appeared to run gingerly toward first. He was removed after that inning.
Yost said Dyson injured the oblique during the at-bat.
Jeffrey Flanagan is a reporter for MLB.com. Follow him on Twitter at @FlannyMLB. This story was not subject to the approval of Major League Baseball or its clubs.