After driving in a run to give the Orioles a 1-0 lead in the top of the first today at Chicago, Adam Jones did not take the field in the bottom of the first.
Jones left with what is called a "mild mid back muscle spasm," and was replaced by Felix Pie.
MASN replays showed Jones grabbing at his back during his first-inning at bat.
Jones entered today in an 0 for 13 slump and batting just .130 over his last 12 games. He lined a single to left in the first to score Brian Roberts, who had doubled.
Jones began today batting .281-19-69 on the year.