On the second pitch of the game, Bonifacio grounded out to short, but he never left the batter's box. As he swung, he fell to the ground, grimacing in pain. Head athletic trainer PJ Mainville had to support Bonifacio as he limped off the field.
Cubs manager Rick Renteria said he did not get a chance to talk to Bonifacio before he left, and did not know the severity of the injury.
Junior Lake switched from left to center to fill in for Bonifacio, and Chris Coghlan came off the bench to play left. The Cubs have been carrying an extra pitcher, and playing shorthanded as far as position players go.
Bonifacio is 1-for-11 in his last four games, but he's been the most versatile player on the Cubs, starting 36 games in center, 19 at second, and one at third. He batted .337 in the first month of the season, but has cooled off since, hitting .222 in 10 games this month.
Outfielder Ryan Sweeney, who has been on the disabled list since May 3 with a right hamstring strain, was scheduled to make a rehab start Thursday for Class A Kane County but was scratched from the Cougars' lineup. He could be headed to Philadelphia to join the big league team. Sweeney batted .200 in 20 games before he was injured.
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.