Ciriaco, an International League All-Star, was hitting .301 at Pawtucket. He may even get the starting nod at second base, though that will be determined later.
The Red Sox may have a second move because outfielder Scott Podsednik is ready to rejoin the team after a rehab stint. That would require moving one of Bostonís outfielders. Ryan Kalish can be sent down and Brent Lillibridge hasnít been used much.
The Red Sox will have to make a 40-man roster move for Ciriaco.
Pedroia reinjured his right thumb in a different area from the injury that caused a tear on the inner half of his thumb near his palm on May 28. He missed six games with that injury, but hit only .210 with seven extra base hits and 105 at-bats after that.
The Sox are also expected to see the return of Will Middlebrooks this weekend, but not today.