Olt was batting .139 in 72 games, but did lead all National League rookies with 12 home runs. He also has struck out 84 times in 187 at-bats.
"He acknowledged he's gotten into a few bad habits at the plate, and bad habits that he couldn't break out of at the big league level," Cubs president of baseball operations Theo Epstein said Wednesday. "I think playing every day down there will be good for him.
"We think he has a chance to right himself just by playing every day and being more relaxed and taking some of the things he's practicing in the cage into the game with him and right himself and get back up here," Epstein said. "I think it was the appropriate move at the appropriate time."
Cubs manager Rick Renteria also met with Olt.
"He wants to get back on track," Renteria said. "I think he felt pretty comfortable about what we were going to try to do and get him as many at-bats as we possibly can."
The Cubs have top prospect Kris Bryant at third base at Iowa, and Olt will play first and also be the designated hitter. He was driving from Chicago to Des Moines on Wednesday, and expected to play Thursday.
"He wants to get down there and work," Renteria said. "He wants to get better."
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.