Weber (1-2) was hit with the loss after surrendering a run on a hit and a walk over one inning Sunday against the Angels. He was optioned to Triple-A Pawtucket following the game, Chris Cotillo of MassLive.com reports.
Weber was called upon in the top of the 10th inning in a tie ballgame, but he allowed the game-winning run on a single to right field. The Red Sox have yet to announce a corresponding move following Weber's demotion.