Manager Paul Molitor said that Nolasco, who exited his May 31 start in the second inning with a sore right ankle, is struggling when he attempts to push off the rubber.
"It's still causing him the same symptoms when he tries to do that, the full exertion," Molitor said. "So we are going to try and find an expert in that, a podiatrist. Someone has got to take another look at that foot and figure out a plan here."
Molitor added that surgery is currently not an option for Nolasco, who is 5-1 in seven starts this season with a 5.51 ERA.
"In the short-term -- actually, not very short-term anymore -- it's not improving to a point where he can pitch," Molitor said. "So we've got to figure out a course of action to try and get him back."
Left-hander Tommy Milone was recalled from Triple-A Rochester to fill Nolasco's spot in the rotation and has allowed four runs over 12 innings in two no-decisions.
David Cobb is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.