McCann had to leave the 6-1 victory over the Pirates on Friday night after five innings because of a strain in the right intercostals area. In layman's terms, that is the ribcage.
Last season, McCann spent most of August on the disabled list because of a left oblique strain and never fully recovered, his poor September part of the Braves' late-season collapse.
McCann is listed by the Braves as day to day this time. McCann hopes that is really the case.
"I want to be smart about things and make sure it is a day or two or three instead of a DL stint," he said.
McCann hurt himself when he blocked a ball in the dirt and threw late to second base in the fifth inning trying to prevent a wild pitch. He left the game after batting in the bottom of the inning and grounding out.
Asked how it felt when he swung, McCann shook his head.
"It didn't feel good," he said.
As David Ross finished the game behind the plate, McCann iced the sore area. A lot more will be known about the seriousness of the injury after he returns to Turner Field on Saturday.
McCann called his leaving the game "just a precaution" and added, "I want to be sure it heals up."
But it isn't known how long that might take.
"We'll know more tomorrow," Braves manager Fredi Gonzalez said. "It's up high between the ribs. We've not really overly concerned. If it is with the oblique, it is a different story."
McCann, who has made the National League All-Star Team in each of his five full seasons, is batting .250 this season with three homers and nine RBIs.
Guy Curtright is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.