Josh Hader going on the injured list was part of a series of moves the Astros made Tuesday involving their bullpen.

Hader, 31, has pitched just three times in August, with his most recent appearance (on Aug. 8) doubling as his seventh this season in which he's logged four or more outs. He's been highly effective overall, tallying a 2.05 ERA (202 ERA+) and a 4.75 strikeout-to-walk ratio.

Losing Hader for any length of time would cripple a club that at one time this season had 18 players on the injured list.