The 19-year-old Academy graduate will team up with County for their Skrill North match at Worcester tomorrow.
Oates, a first-year professional with the Reds, will spend at least one month with County up to and including Saturday 1st March, 2014.
Rhys told barnsleyfc.co.uk, "I'm looking forward to getting some more valuable match minutes under my belt and, hopefully, I'll bag a few goals for Stockport, too."