Arguello, 25, went 7-5 with a 2.55 ERA in 22 starts last season at Double-A Corpus Christi, where he was named the team's Pitcher of the Year. Esposito, 31, appeared in two games for the Astros in September after spending the entire season at Triple-A Round Rock and hitting .225.
Hernandez, 28, hit a combined .220 in 54 games for the Astros and Indians last season and was claimed off waivers by the Astros on July 21. Navarro, 26, split last year between Houston and Triple-A Round Rock, where he hit .271 in 81 games.
Valdez, 27, did not pitch in a regular-season game until August and made 13 appearances at Corpus Christi and the Astros' Gulf Coast League affiliate, posting a 1.10 ERA in 16 1/3 innings. He has pitched in the Minor Leagues for 10 seasons.
Fien, 27, is a relief pitcher who spent all of last season with the Detroit organization and appeared in two games for the Tigers, who picked him in the 2006 Draft. Rodriguez, 26, pitched last season at Triple-A Salt Lake in the Angels' system and was 4-6 with a 5.92 ERA in 31 games (17 starts).
Wolf, 28, made 11 relief appearances in two stints with Oakland last season, posting a 4.26 ERA and no decisions. He has appeared in 25 Major League games in his career with Florida (2007) and Oakland (2010) and has a 7.92 career ERA.
Also, the Astros announced Friday that Carl Schneider has been promoted to the position of clubhouse and equipment manager. Dennis Liborio, who has served as equipment manager since 1979, will assume the role of clubhouse manager emeritus.
"Dennis Liborio has been a huge part of the Astros for over 30 years and will continue to be part of our fabric," general manager Ed Wade said. "The ability to promote Carl Schneider comes about primarily because Dennis hired Carl and groomed him for this opportunity. The Astros are very fortunate to have two loyal guys like Dennis and Carl in our organization."
Schneider, a native of Pasadena, Texas, has worked in the Astros' clubhouse since 1989 in a variety of capacities. He was a bat boy and clubhouse attendant for six seasons (1989-94) before being named the assistant equipment manager in 1995. He held that post for another 16 seasons before this promotion to clubhouse and equipment manager.
Liborio's 2011 season will be his 32nd with the Astros and his 39th in professional baseball. He began his career as a bat boy and clubhouse attendant for the Red Sox in 1969 and held that post through 1973. In 1978, he was named the assistant equipment manager for the Dodgers, a position he held for two seasons until being named the Astros' equipment manager in 1979.