Miller was optioned to Triple-A Pawtucket on Friday, Tim Britton of the Providence Journal reports.
Brock Holt's return from the disabled list spells the end of Miller's brief stint with the big league club as he'll head back down to Pawtucket on Friday. Miller went 0-for-1 in his lone at-bat while with the Red Sox. Given his average production at Triple-A on the season (.256/.324/.300), Miller figures to be an emergency option for a call-up later in the season if Boston incurs another rash of injuries to the infield.