After Saturday's game, Cubs manager Dale Sveum said they would have a better idea as to the severity of Sweeney's injury on Sunday.
Julio Borbon took over in center in the fourth for Sweeney, who has gotten the majority of playing time since David DeJesus sprained his right shoulder colliding with the center-field wall at Citi Field June 14. DeJesus is on the 15-day disabled list.
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.