Williams (undisclosed) was scratched from Thursday night's lineup against the Astros, Martin Gallegos of MLB.com reports.
Williams was scratched from Thursday's contest versus Houston with upper-body soreness, Martin Gallegos of MLB.com reports.
Pena (wrist) is starting at shortstop and batting leadoff for Thursday night's matchup against the Athletics, Brian McTaggart of MLB.com reports.
The Astros selected Barrosa from Triple-A Sugar Land on Thursday.
The Astros designated Alexander for assignment Thursday.
The Astros placed Varsho on the 10-day injured list Thursday, retroactive to Wednesday, due to left wrist inflammation.
Barnett will start Thursday's game against the Astros in Sacramento.
Butler went 2-for-5 with an RBI and was caught stealing in Wednesday's 7-3 win over the Angels.
Hader (4-2) took the loss Wednesday against the Mariners, allowing two runs (one earned) on two hits and four walks across 1.1 innings.
Pena (wrist) stole a base as a pinch runner in Wednesday's 6-5 extra-inning loss to the Mariners.
