Manager Rick Renteria said both players were undergoing tests to determine the extent of their injuries.
The Cubs recalled Logan Watkins and Jorge Soler from Triple-A Iowa to take their spots on the roster.
Sweeney, who was batting .251, had to leave Tuesday's game after one at-bat because of the injury. He said he injured it running to first base in the second inning. Sweeney missed time in June because of a right hamstring strain.
Ruggiano was batting .323 in his last 44 games with nine doubles, four homers and 20 RBIs. He said his ankle has been bothering him for the last two weeks, and he has not started a game since last Thursday.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.