Manager Trey Hillman said the ailment is not considered to be serious. Grudzielanek will be examined by team physician Dr. Steve Joyce.
"If this was during the season, it would not be a [disabled list] situation," Hillman said. "But better earlier than later."
Grudzielanek, who underwent two surgeries on his left knee last season, was being worked slowly into the Spring Training schedule. He made his Cactus League debut last Friday and has played in three games, going 0-for-6.
"I think he gets checked out tomorrow morning, and he'll be back tomorrow night. We're just being cautious and over-aggressive," Hillman said.
"He was a little stiff yesterday and still a little stiff today, so we sent put him on a flight to go out."
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.