The Red Sox designated Anderson for assignment Monday.
His removal from the 40-man roster clears a spot for lefty Patrick Sandoval (biceps), who was reinstated from the 60-day injured list. Anderson has appeared in three games for the Red Sox out of the bullpen this season, allowing three runs on eight hits and two walks while striking out six across eight innings. He's spent most of the campaign at Triple-A Worcester, where he's started in 11 of 16 games and has a 4.81 ERA, 1.38 WHIP and 51:21 K:BB across 58 innings.