Franklin Morales confirmed that on Friday afternoon.
Morales told NESN.com MLB reporter Didier Morais that he would indeed be taking Beckett's spot in the rotation on Sunday against the Minnesota Twins. Beckett left his start on Tuesday against the Detroit Tigers after experiencing back spasms on a rainy night at Fenway Park.
Morales has been pitching primarily out of the bullpen as of late after spending a short stint in the Red Sox rotation. He went 2-1 in five starts prior to the All-Star break.