"It got progressively worse from there," he said.
Gyorko said that he's received a cortisone shot and is wary of how tricky these injuries can be, after he watched former teammate, infielder Logan Forsythe, deal with them in recent years.
The Padres have not announced a roster move on Gyorko, but it's all but certain he'll end up on the 15-day disabled list before Friday's game against the Nationals.
The Padres added infielder Jace Peterson from Triple-A El Paso before Wednesday's game. He got the start Wednesday against the Pirates.
Gyorko has the lowest batting average among qualifying players in the big leagues (.162).
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter.Will Laws is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.