Morales, who has had a hard time getting started this season, finally appears to be in the home stretch of being activated.
The lefty is being stretched out as a starter and will get up to five innings and 80 pitches in this start.
Manager John Farrell said the club hasn't decided definitively how Morales will be used when he returns.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.