The team announced that it had claimed right-handed pitcher Sam Demel and infielder Jake Elmore off waivers from the D-backs, while outrighting left-handed pitchers Fernando Abad and Sergio Escalona and right-handers Edgar Gonzalez, Jose Valdez and Kyle Weiland. The club had previously outrighted infielder Matt Downs.
Outfielder Jordan Schafer was also placed on outright waivers and claimed by Atlanta, his former club, putting the Astros' 40-man roster at 36.
Weiland, who missed almost all of the 2012 season with a shoulder infection after coming over in a trade from the Red Sox, has been placed on the roster at Triple-A Oklahoma City, while Abad, Downs, Escalona, Gonzalez and Valdez are all free agents. Escalona had Tommy John surgery in March and missed the entire season.
Demel, 27, spent nearly his entire 2012 season with Triple-A Reno, posting a 4.07 ERA in 56 relief appearances. He allowed just a .237 opponent's batting average, while striking out 75 hitters in 66 1/3 innings pitched.
The Houston-area product made one appearance for the D-backs last season and has appeared in 72 Major League games over the last three seasons (2010-12) for Arizona, posting a 4-4 record with two saves and a 4.95 ERA.
Elmore, 25, hit .344 with 30 doubles, 73 RBIs, 32 stolen bases and a .442 on-base percentage in 108 games for Reno last season. He made his Major League debut with Arizona in August and played in 30 games for the D-backs, including 14 starts at shortstop and one at second base. He was named a Pacific Coast League mid- and postseason All-Star.
Schafer began last season as the Astros' starting center fielder, but numerous injuries and a drop in production -- as well as some concerns about his attitude -- caused him to fall out of favor. He hit .211 with four homers, 27 stolen bases and 106 strikeouts in 313 at-bats with the Astros, but a shoulder injury limited him to 21 at-bats over the final two months.
The Astros have options in center field with Justin Maxwell, who can play all over the outfield, and rookie Brandon Barnes, who made his debut last year and made a handful of highlight reel catches in center. Waiver claim Che-Hsuan Lin can also play center field.
Schafer was cosnsidered one of the top prospects for the Braves before they sent him to Houston on July 31, 2011. In the deal, the Astros also received pitchers Brett Oberholtzer and Paul Clemens -- both of whom reached Triple-A last year -- and reliever Juan Abreu, who is no longer in the organization.
In Schafer, the Astros got a player with plenty of athleticism, but who could never seem to put it all together.
Schafer was pulled from a game in July for what then-manager Brad Mills described as "behavioral reasons," and was out of the lineup the following day. He was arrested last year and charged with possession of marijuana and drug paraphernalia during a traffic stop.
Considered a solid defensive player who can run, Schafer will have a chance to begin the 2013 season as one of Atlanta's backup outfielders.
Abad, 26, went 0-6 with a 5.09 ERA in 37 games, including six starts, for the Astros last season. He has pitched in parts of the last three seasons (2010-12) with Houston, compiling a 5.10 ERA in 82 relief appearances and six starts.
Gonzalez, 29, went 3-1 with a 5.04 ERA in six starts for the Astros last season after having his contract purchased from Oklahoma City on Sept. 3. He has pitched in parts of eight Major League seasons with Arizona (2003-08), Oakland (2009), Colorado (2011) and Houston (2012).
Valdez, 29, compiled a 2.25 ERA in 12 relief appearances after being a September callup for the Astros last season. He spent the majority of his season with Oklahoma City, where he posted a 4.95 ERA with 21 saves in 46 relief appearances.