Yorke (shoulder) is beginning a rehab assignment with Single-A Bradenton on Tuesday, Dominic Campbell of SI.com reports.
Yorke is currently on the Triple-A injured list and hasn't played since June 17 due to a shoulder issue. The 24-year-old opened the season with the Pirates but slashed just .197/.279/.276 with four extra-base hits, six RBI, six runs scored and a 7:17 BB:K across 86 trips to the plate before being demoted.