The 23-year-old Joseph suffered the injury during a home-plate collision in May while playing for Double-A Reading. He attempted to rehab, playing six games in the Gulf Coast League, but he was quickly shut back down.
The Phillies acquired Joseph in a 2012 trade with the San Francisco Giants involving Hunter Pence. After the 2012 season, Baseball America ranked Joseph the No. 3 prospect in the Phillies organization. But he has now lost most of the last two seasons of development to injury. Last season, he played in just 36 games after battling a concussion and its after effects.
At the time of his injury in May, Joseph was off to a promising start to the season, batting .282 with five homers, four doubles, a triple, and 19 RBIs through 21 games.