The Red Sox recalled Weber from Triple-A Pawtucket on Monday, Jessica Camerato of MLB.com reports.
He'll move up to the active roster as a replacement for long reliever Hector Velazquez, who was sent back to Pawtucket following Sunday's 7-4 loss to the Dodgers. Three of Weber's previous six appearances with Boston came as a starter, but he'll work out of the bullpen with the Red Sox recently acquiring Andrew Cashner from the Orioles to round out their rotation.