Cozart planned on taking full batting practice and infield work Thursday before the Reds opened a four-game series against the Dodgers.
"He could have been ready today," manager Dusty Baker said. "I decided not to play him today and we'll wait until tomorrow. This way, he is available late in the game. I'd rather have him late in the game today than having to take him out late."
After enduring some first-half struggles, Cozart has been hot since the All-Star break and was batting .351 (13-for-37) in his last 10 games entering play Thursday.
"I had four hits and have been doing better at the plate and something like this happens," Cozart said. "It's one of those things that if you don't calm it down, it might nag you the rest of the year."
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. This story was not subject to the approval of Major League Baseball or its clubs.