Barnes was placed on the 10-day disabled list Tuesday with a lower-back strain, Ian Browne of MLB.com reports.
The move to the DL comes after Barnes failed to record an out while allowing both batters he faced to reach base in Monday's loss to the Indians. The Red Sox recalled Hector Velazquez from Triple-A Pawtucket to fill Barnes' spot in the bullpen, but it's expected that Joe Kelly and Brandon Workman will be the main beneficiaries of more high-leverage opportunities while Barnes is sidelined.