Manager Andy Green said the Padres want Renfroe to work on plate discipline and getting on base more consistently.
"He's got strides to make," Green said. "If you're going to have a winning culture here, you have to be willing at times to make tough decisions and send guys down that you like as human beings, that you value as teammates, that you think have a good future with your organization but at present aren't quite getting the job done."
Renfroe had 20 home runs but was hitting just .230 with a .285 on-base percentage.
He was called up late last season after helping El Paso win the Pacific Coast League title.
The Padres called up outfielder Jabari Blash to take Renfroe's spot.