"This would be the first year he's played past August. His season would be over in five weeks and he'd be ready to go home," Reds manager Dusty Baker said. "We're trying to program him into territory where he's never been before, which is September and hopefully October. Instead of a five-week season left, he's looking at 13 more weeks hopefully."
Baker also rested third baseman Scott Rolen. Todd Frazier moved over from first base to replace Rolen and Miguel Cairo got a start at first base.
Cozart, who came in batting .240 with nine home runs and 19 RBIs while leading National League rookies in several categories, snapped a 0-for-16 stretch with a single on Tuesday.
"It's not only about Cozart. I've got to play Valdez too," Baker said. "Him and Miggy have the least amount of at-bats here. The other guys in the infield, have either been fortunate enough to play and not get injured or been hot enough to continue to play, like Frazier."
Cozart was in prolonged slumps earlier in the season, including an 0-for-19, an 0-for-13 and an 0-for-12. It's something the Reds expected as they put a rookie in a key position on the field and were prepared to ride it out.
"It's hard watching your kids, but they've got to go through it," Baker said. "At any given time, I could start three kids. It's hard watching Frazier strikeout four times one night and getting two hits the next night.
"What choice do you have? They're the best you have. You're counting on what they are now and hoping to build on what they may be from the experience they get now. You can't rush experience, as much as you would like to."