The left-hander is scheduled for treatment, and the team's going to get a better look after his bullpen session in a few days.
"I'm not that concerned," Williams said. "It's just tightness, and I think that happens to pitchers over the course of a season anyway. I'm not concerned about it. I don't think he is either."
Gonzalez didn't seem too worried in the clubhouse before Thursday's game.
"It feels fine," Gonzalez said. "[Wednesday night it was] a little windy, you tend to tighten up a little bit. So you've got to stay loose, stay warm."
Jeff Seidel is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.