Houston Astros closer Josh Hader was diagnosed with a left shoulder capsule strain and will not throw for approximately three weeks, the team said Friday.

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.