The Astros designated Shewmake for assignment Friday, Matt Kawahara of the Houston Chronicle reports.
With Jeremy Pena (calf) back from the injured list, Shewmake loses his spot on the 40-man roster. The 28-year-old has slashed .256/.272/.423 with three homers, nine RBI, 10 runs scored and a 2:13 BB:K across 83 plate appearances with Houston this season.