Hernandez (oblique) was reinstated from the 10-day injured list Friday, Chris Cotillo of The Springfield Republican reports.
Hernandez began a rehab assignment at Triple-A Worcester on Tuesday and allowed no hits and a walk while striking out one in a scoreless inning during his lone appearance. The southpaw had been on the IL since July 31 but will be available out of Boston's bullpen for Friday's series opener against the White Sox.