The Astros continued their roster shake-up on Monday, announcing that they will officially recall right-hander Chia-Jen Lo from Double-A Corpus Christi and select the contract of fellow righty Josh Zeid from Triple-A Oklahoma City prior to Tuesday's series opener against the Orioles. In a corresponding move, the club optioned another right-hander, Hector Ambriz, to Oklahoma City.
The roster moves come after Houston traded closer Jose Veras to Detroit earlier in the day in exchange for outfield prospect Danry Vasquez.
As for Lo and Zeid, each player will be making his respective debut on a Major League active roster.
Lo, 27, racked up a 3.24 ERA with six saves over 17 appearances this season between Corpus Christi, Class A Quad Cities and Class A Tri-City. He joined Corpus Christi on July 10 and -- after a rocky debut with the Hooks -- has worked 7 2/3 scoreless innings over his last seven appearances.
Meanwhile, Zeid has posted a 4-1 record to go along with 13 saves and a 3.50 ERA in 43 relief appearances this year with Oklahoma City. Since becoming the Red Hawks' closer on June 15, he has converted 13 of his 15 save opportunities.
Ambriz, who was most recently promoted on July 19, will again return to Oklahoma City. In two stints with the Astros this season, the 29-year-old reliever has a 5.70 ERA in 43 appearances.
Paul Casella is a reporter for MLB.com. Follow him on Twitter @paul_casella. This story was not subject to the approval of Major League Baseball or its clubs.